Can text messages increase safer sex behaviours in young people? Intervention development and pilot randomised controlled trial

The theoretical basis of our intervention

The intervention was informed by the capability, opportunity and motivation model of behaviour (COM-B). 23 This is linked to a comprehensive model of behaviour change, the behaviour change wheel, which aims to capture the full range of intervention functions involved in behaviour change. 23 These include education, persuasion, environmental restructuring (encouraging people to change their environment to support the behaviour), training and enablement. Each intervention function can be implemented by a wide range of BCTs. 22

In the case of sexual behaviour, knowledge, beliefs, self-efficacy and skills as well as social and interpersonal influences have important effects on motivation, capability and opportunity. 24,25 Our intervention aimed to influence these factors to reduce sexual risk behaviour. It aimed to support participants in correctly following treatment instructions, by correctly taking their prescribed treatment, telling partner(s) about their infection and avoiding sex for a week after taking treatment. The intervention aimed to encourage participants to use condoms with new or casual partners and obtain testing for STIs for themselves and their sexual partner(s) prior to unprotected sex (see Figure 2 and Appendix 1).

Generating content

We identified factors influencing safer sex behaviours using evidence from systematic reviews of the literature. 24,26 We generated messages, selecting intervention functions23 and BCTs that might be employed to influence these factors.

We identified trials of interventions promoting safer sex behaviours that reported STI outcomes in a systematic review6 and obtained the protocols, the content of which was coded using Abraham and Michie’s14 and Michie et al. ’s27 2011 taxonomy of BCT. We computed the inter-rater reliability (Cohen’s kappa and percentage agreement) for the scoring of the presence/absence of BCTs. We described the BCTs identified in face-to-face interventions reporting statistically significant reductions in STI infection at follow-up. Messages were drafted to include all those BCTs that we had identified in effective face-to-face interventions and additional BCTs shown to be effective in changing other behaviours. We adapted them for delivery by text message where necessary.

To ensure that the intervention content was informed by technical experts and those experienced in working with young people on safer sex behavioural support, a sexual health counsellor (Melanie Otterwill) generated messages. Experts in sexual and reproductive health service delivery, research and public health (PB, KW, RF, JB, KD, CF) reviewed the messages and were asked to identify additional content that they considered should be included in the intervention.

Generating the automated information technology system for delivering the messages

An IT programmer developed an automated text messaging system to deliver the intervention, which had an automated link to the randomisation system and database.

Testing and refining the messages: obtaining user views in focus group discussions

We convened focus groups of people aged 16–24 years to seek their preferences regarding the intervention and modify the messages based on their views regarding their acceptability. We recruited participants attending community sexual and reproductive health services in an inner city in the south of England (south-east London), a city in the north of England (Greater Manchester) and a rural area (Cambridgeshire). Clinic staff invited participants to join the focus group discussions. A researcher provided verbal and written study information. Groups were single sex, including teenagers and those in their 20s. We obtained informed written consent from participants. We explored the participants’ preferences regarding the intervention and sought their comments on the preliminary messages, specifically with regard to their acceptability, and suggestions for improvement. A second facilitator made notes during the meeting regarding their views and suggestions for improving messages and, with participants’ agreement, recorded the meeting. Participants received £20 in thanks for their time. Data were stored confidentially and anonymised in publications or reports. According to the feedback received in the initial focus groups, we retained, discarded or modified messages and retested them in subsequent focus groups or by e-mail. We continued refining the messages and conducting focus groups until participants reported that the messages were acceptable, comprehensible and appropriate.

Testing and refining the messages based on feedback obtained in a survey

The messages modified by the focus group participants were then tested in a survey and adapted based on survey responses. We recruited young people from community sexual and reproductive health services located in south-east London and rural Cambridgeshire. The eligibility criteria for the survey were age 16–24 years, ownership of a personal mobile phone and either testing positive for chlamydia or reporting unsafe sex in the last year (more than one partner and at least one occasion of unprotected sex). The researcher working in the clinic provided written and verbal information and sought informed written consent. We offered participants a private room in which to complete the questionnaire.

We selected any messages for which the feedback had been ambiguous in the focus groups and a random selection of other messages for testing. The questionnaire asked participants to score each of the messages using a 3-point scale on how relevant they considered them to be (relevant, unsure or not relevant). They were asked to identify messages that were hard to understand or that they did not like and to provide suggestions as to how the messages could be improved. Participants received £5 for completing the questionnaire. We conducted a descriptive analysis reporting the scores for each message using Microsoft Excel^® 2013 (Microsoft Corporation, Redmond, WA, USA). We removed or adapted messages that achieved low scores for perceived relevance.

Testing and refining the messages based on feedback regarding the intervention when delivered to participants’ mobile phones

The resultant messages were delivered to participants’ mobile phones and final adaptations were made based on their feedback about the intervention obtained in telephone interviews. Clinic staff identified potential men and women in their teens and early 20s who had been diagnosed with chlamydia. If they agreed to take part their details were passed to OM. OM recruited participants by phone and provided verbal and written information by e-mail to potential participants and asked them to text their consent. After obtaining informed consent, the text messages were sent to participants from our automated computer-based delivery system.

Seven days after enrolment, OM contacted the participants by phone and asked them for further feedback regarding the intervention. OM asked participants about the appropriateness of the timing, frequency and content of the messages and their experiences when trying to implement the advice in the messages. Based on their feedback we made further modifications to the intervention. We continued to recruit participants until no new data regarding how the intervention should be modified emerged from the interviews. Participants received £20 in thanks for their time.

Content derived from evidence on barriers to safer sexual behaviours

In Table 1 we describe key evidence-based barriers to safer sexual behaviour and how our intervention addressed these and which BCTs and which functions from the COM-B behavioural theory we employed. The principles informing the content of the intervention based on evidence on factors associated with safer sex are also reported in Table 1.

Content derived from behaviour change techniques in effective face-to-face interventions promoting safer sexual behaviours

The BCTs identified in face-to-face interventions reporting statistically significant reductions in STI infection at follow-up are reported in Table 2. 27 The agreement in coding the BCTs in trials of all behaviour change interventions reporting STI outcomes was 100% except for goal-setting (kappa 0.74, agreement 90%), demonstrating condom communication (kappa 0.74, agreement 90%) and encouraging practice of condom communication (kappa 0.74, agreement 90%). In our intervention we included 21of the 25 BCTs found in effective face-to-face interventions when coded according to Abraham and Michie’s taxonomy of BCTs. 14

Content derived from expertise

To ensure that the intervention content, tone and style were informed by technical experts and those experienced in communicating with young people regarding safer sexual behaviours, a sexual health counsellor (Melanie Otterwill) generated messages. Experts in sexual and reproductive health service delivery, research and public health (PB, KW, RF, JB, KD, CF) reviewed the messages and were asked to identify additional content that they considered should be included in the intervention.

Content derived from focus group discussions

We convened eight focus groups with 82 participants (nine of whom attended two focus groups). The focus groups included 32 men and 50 women and the median age of participants was 17 years. In total, 39 participants were from London, eight were from Manchester and 35 were from rural Cambridgeshire (Table 3).

Participants’ views regarding the messages informed the tone, style, language, punctuation, frequency and duration of the messages, the content of the messages and the way that BCTs were operationalised. Young people wanted messages in a non-judgemental, credible tone that they ‘could relate to’. The preferred style of messages was those containing practical information about what needs to be done, why and how, for example:

You can make sure you don’t get another infection by (1) getting the person you are having sex with treated, (2) using condoms every time you have sex, (3) you and your partner getting tested before sex without a condom and (4) having another test in 3 months.

They identified messages that were too negative, for example ‘I was shocked when I was told I had it’.

They also wanted to know how to carry out behaviours, for example starting a conversation about having a STI was seen as particularly challenging. Messages needed to avoid ‘patronising’ content or ‘telling people what to do’. They wanted exclamation marks to be avoided, as these were also experienced as patronising, for example ‘Having a test can feel like a big step. You did it!’

In terms of other aspects of language and punctuation, participants wanted messages to be easy to understand. They wanted slang terms to be avoided and some phrases or terms such as ‘your man’ were considered overfamiliar and to be ‘trying too hard’ to identify with youth culture, for example ‘Not sure how to convince your man to wear a condom? Text 3 for some tips’.

Focus group participants identified messages that did not meet these criteria and made suggestions about how they could be altered or improved. An acceptable frequency of messages was up to four a day, with message frequency reducing within the first 2 weeks.

When asked to give feedback regarding the messages, participants reported particularly liking short, positive and non-judgemental messages, for example:

If you make it a habit for you and your partner(s) to get tested before you have sex, you can avoid a lot of hassle and regret later.

They identified messages that were supportive and reassuring, for example:

You made the right decision to get a test. Getting treated quickly means you are less likely to have any problems.

They liked messages describing other people’s experiences of how they told a partner about an infection or how they dealt with other sexual health issues such as condom use problems:

Some people say they didn’t use a condom because their partner didn’t want to use one. If you’d like to hear how other people convinced their partner to use one text 3.

Here is an example of how others told their partner: ‘I said I don’t really want to tell you this but I have to – I found out I have chlamydia. It’s awkward to tell people but it’s not right not to, is it? They may not know. You can’t just let them walk round with an infection’.

‘I just couldn’t tell some partners so the clinic offered to do it for me. They gave me the option of keeping my name out of it’. Text 7 to hear more.

Although the intervention content that we developed based on the content of effective face-to face interventions was mostly appreciated, some content had to be adapted or removed, such as messages in which the content did not resonate with participants’ experience or messages that were ‘unrealistic’, for example:

One possible benefit of knowing that you’re safe is that you might enjoy sex more.

Participants reported that the text message designed to ‘review participants’ behavioural goals’ by asking if participants had told their partner about an infection was ‘too intrusive’. Some messages involving ‘action plans’ that encouraged participants to consider when, where and how they would carry out a behaviour were also considered ‘too intrusive’ and these were mainly reframed as suggestions regarding when, where and how a behaviour could be carried out, for example:

A lot of the time, sex isn’t planned. So it’s best to always have a condom on you. Find a time to put a few in your wallet. You could also keep a supply in places where you have sex (bedroom, partner’s house, car).

Men and women reported that messages covering gender roles, relationships and sexual pleasure were ‘too personal’ and ‘intrusive’ when delivered by text message and so this content was removed from the intervention.

Heterosexual men and women found messages about sexual pleasure without sexual intercourse ‘unrealistic’ and felt that this content reduced the credibility of the intervention, for example:

There are other ways of having safer sex without having intercourse. This might include kissing, fantasising, touching and mutual masturbation.

There were no clear differences in feedback on the content of the messages according to urban or rural residence. Men reported that they were able to negotiate condom use and so this content was included only for women.

Adapting the content based on a survey

In total, 100 participants were recruited and completed the questionnaire, of whom 74 were women and 26 were men (Table 4). The data set was 98% complete, with five instances of missing data.

Of the 19 messages tested in women, there were three that < 40% of women scored as relevant and > 30% of women scored as not relevant (see Appendix 6, Table 12). One of these messages had received mixed feedback in the focus groups and was discarded from the message set. The other two messages were modified based on feedback obtained from the focus groups. For each of the remaining messages, the number of respondents reporting that the message was relevant ranged from 36 out of 74 (49%) to 66 out of 74 (89%), a median of 51 out of 74 respondents (69%).

Of the 17 messages tested in men, there were four messages that < 40% of men scored as relevant (see Appendix 6, Table 12). Two of these had received ambiguous feedback in the focus groups and were discarded. One received positive feedback in the focus group and was considered to be important and so was retained (‘You made the right decision to get a test. Getting treated quickly means you are less likely to have any problems. Text 2 to hear about how others felt when they found out that their test was positive’). One was modified based on further feedback obtained from participants: ‘You might be thinking about how they’ll react when you tell them. It might help by warming up the conversation and easing into it’ was changed to ‘You might be thinking about how they’ll react when you tell them. You could try practising what you’re going to say’. For each of the remaining messages, the number of respondents reporting that the message was relevant ranged from 12 out of 26 (46%) to 24 out of 26 (92%), a median of 18 out of 26 respondents (69%). No messages were considered ‘hard to understand’ or were ‘disliked’.

Testing and adapting the content based on telephone interviews with users after sending the text messaging intervention to users’ mobile phones

The eight participants who took part in the interview study, six women and two men, had a median age of 20 years (average 19 years). Six participants were from south-east London and two were from Cambridgeshire and participants were from a range of ethnic backgrounds (including white British, black British African, black British Afro-Caribbean and mixed ethnicity).

Participants were positive about the intervention content and delivery. In general, participants found the information in the messages useful and relevant to someone who has just received a positive chlamydia test result. They thought that the messages made them more aware of what chlamydia is and how to prevent it.

I think in general it was really good, like it was really helpful, it helps you know everything and gave you all the right information.

ID6

A few participants expressed a strong engagement with the messages, with one reporting that she discussed the information in the messages with friends and another saying that she kept the messages on her mobile phone because she valued the information in them and was planning to share them with her younger cousins:

I think I will keep it on my phone because I think it’s good information. I’ve got like younger cousins and stuff and now I have more information that I can tell them, I think I’m going to use it in that way.

ID5

It’s in my mind now.

ID2

You send me messages, I speak with friends or many people about chlamydia this week because it’s good information.

ID7

One participant commented that she was disappointed when it ended and that she goes through the messages in her room at night when she thinks a lot more:

I go back through my texts, say I was reading them . . . like when I’m in my room at night, I think a lot more, so when I go through my texts, they did kind of make me think a lot more.

ID3

A few comments were less complimentary. One found the message that ‘chlamydia is a common bacterial infection’ a bit ‘scary’ (ID1). An older participant (aged 23 years) said that he thought that some of the messages were a bit ‘silly’ (ID4). One participant indicated that some people might have trouble understanding the messages:

Well, some people are not going to understand because some people, like it’s difficult for them.

ID1

All but one participant reported that they told their partner about their infection. However, the participant who had not yet told her partner expressed an intention to tell him:

It might change his view on me, so it’s kind of scary, but I realise that I do need to do it. It would be better for me and him if I tell him.

ID3

One said that she would have told her partner anyway:

I was planning on telling him but I think it just gave me a push.

ID2

Two participants told their partner about their infection before they started to receive the messages. Four participants attributed telling their partner about their infection directly to the messages:

I forgot, innit, because I don’t want . . . like if I have sex with a girl that I don’t know, yeah, it’s just like maybe that just that one night, yeah, it’s over, I don’t want to know you again, like so . . . well, obviously I’ve got on my BlackBerry thing, so I pinged that, I was like ‘uh, you need to go check out yourself in the clinic, innit’. I didn’t tell her what I got.

Do you think if you didn’t get the text messages that you would have told her?

Well, I wouldn’t because the day I came here, you just gave me the pill then, I forgot about everything.

Another said that he ended up telling his partner about his infection because the texts were making him feel guilty for not doing so:

And how did you tell them?

I said um [laughs] I kind of ripped it off, you know like a plaster, like I just ripped it off, just ripped the plaster off. It just made me feel guilty, made me feel guilty for not telling so I had to tell someone.

One participant said that she did not know that chlamydia could be treated. She said that the clinic told her that it is treatable but she only realised that the infection was not too serious after receiving the messages:

I thought that Chlamydia was like, once you get it, you don’t get rid of it.

But, even though they told you that, what was the difference of receiving the text?

Because it was more than one person telling me, I felt, ‘OK, well, maybe it’s not that bad’ because I was a bit down and, yeah.

She said that she used a condom during the week after she was treated because the clinic had given her condoms and the messages reinforced the advice not to have unprotected sex during this time:

It was because of everything, really, like the texts and what the clinic told me. But, I guess, if the clinic didn’t give me condoms and you just texted me, then I probably wouldn’t have, but because they gave me condoms and they told me, and the text told me, it was like, it made things more serious and I realised like I don’t want to infect anybody I know.

ID3

Most thought that the tone of the messages was appropriate, although one participant thought that the messages sounded too automated and could have sounded more ‘humany’ (ID3).

Some participants gave feedback about the length of the messages and the timing and frequency of message delivery. Five recipients were happy with the frequency and one wanted more messages. Two recipients reported that there were too many messages, one of whom said that he was enjoying the messages at first but that it became too much after five or six messages and he wanted them to stop.

At what point did you want it to stop, like how far into it?

Like when obviously like five or six messages, I was like ‘oh, that’s too much now’ but it’s like the same thing, they’re saying the same thing but different words over and over again, so that’s kind of annoying.

Most thought that the length of the messages was about right:

I think they are not too long and they usually have the most important thing in the first sentence so they don’t try to say more, they just said what is important and I think that is great.

ID8

Most participants were unconcerned about keeping the messages confidential. Those who were concerned reported being confident about knowing how to protect their mobile phone and prevent others reading messages.

Participants reported that they especially liked the messages giving examples of how others had told their partner about having an infection. Based on this feedback we included the content about how others had told a partner about their infection in the core message set, rather than as part of the optional messages. An older male participant pointed out that the message ‘That’s great if you’ve told your partner . . .’ would make someone who has not told their partner feel bad. As a result we removed this message. No new issues were emerging in interviews and so no further participants were enrolled. We also ensured that information was included in the intervention that simply replying ‘stop’ to any messages would result in no further messages being sent.

Intervention content for the pilot trial

The final message set was tailored according to sex and infection status at enrolment [no infection, chlamydia, gonorrhoea or non-specific urethritis (NSU)]. The message sets for those diagnosed with a STI were similar to each other except that the information provided was specific to the STI diagnosed. The number of messages targeting each behaviour and the number of messages employing specific intervention functions and BCTs are described (see Table 6).

For those diagnosed with a STI, messages over the first 3 days focused on engaging with the study, getting treatment, taking treatment and providing information about the infection. Over the next week messages targeted telling partner(s) about an infection. The messages provided non-judgemental, non-stigmatising information covering how common infections are; that an individual may not have symptoms and so may be unaware that they have a STI; that many people diagnosed with a STI have had only one sexual partner in the previous year; and that infections are easy to treat. Messages provided information about how to prevent infections. They provided suggestions about when, where and how to tell a partner about an infection and examples of how others told their partners, covering a range of different types of relationship (e.g. casual, long term). The messages then provided links to services that could inform partners and links to support for anyone concerned about violence in their relationship after telling a partner about an infection. Messages also aimed to provide social support, acknowledging people’s experiences.

For those diagnosed with an infection, after day 14 the messages targeted condom use and testing for STIs before having unprotected sex with a new partner. Participants who had not been diagnosed with an infection were sent the messages about safer sex behaviours (condom use and testing for STIs) starting on day 1. Over the following 30 days messages were sent providing information on how to prevent infections and how you cannot assess risk according to how well you know someone or by their appearance. Messages included instructions on how to use condoms, emphasised positive aspects of condom use and provided tips on preventing condom problems and examples of how others resolved condom use problems. Participants were prompted to think about risks that they had taken and what they could do differently in the future and also to consider how they had carried out safer sex behaviours in the past. Text messages included advice about getting tested before unprotected sex with a new partner. Participants were sent links to further web-based information about contraception, alcohol and sexual risk, how to use a condom and general communication about sex. Women were sent messages covering how other women had negotiated condom use. The messages were designed to provide social support for safer sex behaviours.

Control

The set of control messages consisted of 13 messages in total, which were spaced 30 days apart starting from the point of randomisation (see Table 6). The control messages contained no BCTs or information regarding sexual health. The messages were intended to help keep participants engaged in the study and to remind them of their participation, for example ‘Young people can experience health inequalities. Taking part in the texting study can help things to be equal. Thanks for taking part’. The messages expressed our appreciation of participants’ involvement in the study and suggested that participation in research can be personally beneficial: ‘Taking part in the texting study is a way to help you be actively involved in things that affect your life. Thank you for taking part’.

The information technology system delivering the messages

The IT system developed for message delivery was designed to be automated and to deliver different content according to allocation (intervention or control) and, for those receiving the intervention, according to participant characteristics (STI status and sex). Interactive messages could be sent in response to key words sent to the system from participants’ mobile phones requesting more content on specific topics. The system is held on a secure server with secure access. The system was fully tested with ‘dummy’ participants and the research team members’ mobile phones to check that the correct set of messages was delivered according to participant characteristics (STI status and sex) and the prescheduled time frame and to test that interactive content sent in response to key words was sent in accordance with the intervention protocol.

Key findings

We have described the development of a theoretically informed intervention designed to address barriers to safer sex behaviours and increase safer sex behaviours in those aged 16–24 years diagnosed with a STI or reporting unprotected sex with more than one partner in the last year. We have described how the intervention content was derived from theory, evidence-based BCTs identified in effective face-to-face safer sex interventions, evidence regarding barriers to safer sex and expert and user views. Focus group discussions, a survey and telephone interviews with users informed and refined the intervention to ensure that it was acceptable to young people. In the survey participants reported that all of the messages were easy to understand and none was disliked.

Strengths and weakness of the intervention development work

Our work on intervention development has some weaknesses: although the intervention content associated with increased self-reported condom use is known,28 it remains unclear which BCTs are associated with increased effectiveness at reducing the incidence of STIs. We therefore included all of the BCTs in face-to-face interventions evaluated by randomised controlled trial and reporting reductions in the incidence of STIs at follow-up. To develop an intervention that was acceptable we excluded content that participants found to be unacceptable or irrelevant. Some evidence-based BCTs were modified based on feedback from young people and the effectiveness of the ‘acceptable’ but modified content is not yet known. Although the current intervention is tailored by infection status and sex, it is not tailored according to specific personal issues with regard to adopting safer sex behaviours. Thus, messages sent may not all be directly relevant to every participant. During the conduct of our work a new internationally agreed taxonomy of BCTs was published. 14,22 We included BCTs defined according to an older taxonomy in our intervention, but coded the final intervention using the new internationally agreed taxonomy. The intervention requires further adaptation to ensure that the content is appropriate for men who have sex with men and women who have sex with women.

Discussion in relation to existing research

In keeping with current guidance29 we used theory, evidence and testing to develop our complex intervention. The approach that we used to develop our behaviour change intervention based on theory, evidence regarding barriers to behaviours, evidence regarding the content of effective interventions and user views is not new. 30 There is no evidence that the content of interventions delivered by text message targeting safer sex has previously been based on a process designed to identify and then target documented barriers to safer sex behaviours. No previous intervention delivered by mobile phone informed by the COM-B comprehensive model of behaviour change has been reported. The recent development of validated taxonomies of BCTs allowed us to code the content of face-to-face interventions using a valid and reproducible methodology. There are no reports of previous interventions being developed based on empirical evidence regarding the content and BCTs employed in effective face-to-face interventions targeting safer sex behaviours. Our intervention includes content addressing attitudes, information and behavioural skills, which are found in the most effective interventions promoting condom use. 28 Our intervention includes a larger number of BCTs than previous interventions. No previous trials of interventions delivered by mobile phone have targeted the correct treatment of existing STIs, including providing support for telling partners about a STI. We ensured that the content of the text messages is consistent with the British Association for Sexual Health and HIV current safer sex advice,31 which recommends focusing on increasing motivation, skill acquisition (including communication skills) and provision of information about safer sexual practices.

Implications for the research project

The intervention was used in the pilot trial (see Chapter 4).

Step 1: identifying evidence-based effective strategies to increase follow-up in trials

We searched for existing systematic reviews of trials of interventions designed to increase follow-up in research and contacted Public Health England’s Chlamydia Screening Programme team to identify any unpublished trials of interventions designed to increase response rates to postal STI test kits. We identified methods in systematic reviews for which there was there was good evidence (p ≤ 0.05) of success in increasing response to postal follow-up requests in trials. We developed prototype follow-up procedures incorporating the effective strategies identified (Table 5).

Step 2: testing prototype follow-up procedures and materials

Sample postal testing kits routinely used in Cambridgeshire, Manchester and south-east London (our trial recruitment sites) and STI test kits used in NHS chlamydia postal testing services were obtained by OM. Successful receipt of the postal STI testing kit depended on the kit fitting through participants’ letterboxes. OM measured a range of London letterboxes on central London streets and measured the test kits to identify those that would fit through the smallest letterboxes measured. OM and CF attempted to complete all prototype follow-up procedures to identify barriers to follow-up completion and refine procedures to make follow-up as easy as possible.

Two researchers (OM and CF) attempted to follow the instructions for providing urine and swab samples that were included in postal STI testing kits that fit through the smallest letterboxes and completed the forms. Based on this experience, we generated ideas on how to make the follow-up processes easier. OM generated prototype test kits including combinations of the original materials and the newly generated materials (a choice of a vaginal swab or urine collection tube for women, a urine collection tube only for women and men and a swab only for women; a cone or pouch urine collection tube; a blue or brown envelope). OM provided volunteers from the London School of Hygiene & Tropical Medicine’s (LSHTM) Clinical Trials Unit (CTU) with test kits and asked them to provide samples (which were disposed of) and feedback regarding their experience of completing the test. We consulted with experts in sexual health regarding the questionnaire design and follow-up procedures.

Step 3: consulting with users

See Chapter 2 for focus group methods.

We held one participant representative group to obtain the views of participants regarding the trial questionnaires and follow-up procedures and also asked participants for their views regarding trial follow-up procedures during focus group discussions convened to inform the development of the intervention. People aged 16–24 years who owned a mobile phone were eligible to take part. We asked for participants’ views on the pilot trial questionnaires, level of incentive offered and the acceptability of postal follow-up and materials (e.g. chlamydia test kit, envelopes).

Effective strategies to increase postal follow-up

The follow-up strategies for which there is good evidence of increasing the odds of response according to systematic review and trial evidence38–44 are reported in Table 5. We employed all except four of the strategies. We did not send post by recorded delivery as users reported that recorded delivery would be unacceptable to them as they were concerned that it would draw parents’ attention to the package. 38,39,44 For the same reason we did not add a ‘teaser’ on the envelope (mentioning that there may be a benefit to opening). 38 We did not include a statement about an obligation to respond to the request because our sexual health expert group thought that our particular target group might respond negatively to this. 38

Testing the prototype follow-up procedures

The smallest London letterbox that OM measured was approximately 19 cm × 2.5 cm. The most appropriately sized postal testing kit that we found was provided by a laboratory diagnostic company and contained prepackaged components. The test kit included nine items: a urine sample tube and urine collection pouch (males and females), a vaginal swab tube (females only), a laboratory request form, a sample instruction leaflet, a chlamydia information leaflet, a business promotional card, a condom and a pen.

It was found by OM and CF that the components in the postal testing kit included many non-essential items. When CF opened the box all of the items fell out. Based on this experience we removed all but the essential content. CF broke the urine collection pouch when she attempted to open it and OM was unable to open it. Volunteer staff in the CTU (n = 12) were asked to provide a urine sample in the pouch. Only one person successfully used the pouch. The others broke it when they opened it, could not open it or did not know what it was for so did not use it. As an alternative four people were provided with a urine collection cone. No one reported difficulties in using the cone to collect urine or urinating directly into the urine sample bottle (men only).

The two sets of instructions were found to be overly complicated by OM and CF. The instructions for women could be confusing because they received a postal testing kit with both the swab and the urine tube but were required to provide only one sample. We provided the CTU volunteers with the original instructions or simplified instructions and found that they preferred the shorter instructions. Female CTU staff volunteers did not express a preference for providing a urine sample or a vaginal swab. CTU staff suggested that we include a statement in the postal letter to participants about the importance of their participation so that they would feel ‘proud’ about doing something good.

Experts in sexual health questionnaire design suggested that we list the key questions – those on treatment and sexual health behaviour – first.

User views

The focus group participant demographics are provided in Table 3. Participants wanted the questionnaires to be as short as possible. They had no objections to the prototype questionnaire design or content. They reported that the envelope used to send postal follow-up materials should be identifiable only to them. They suggested using a coloured envelope so that they would know what it was without others knowing. They reported that the short version of the sample STI test kit instructions was clear and acceptable. Participants asked to receive a text or phone call before we sent the questionnaire and STI test kit so that they would know to look out for them. They were concerned that sending follow-up materials by recorded delivery could call attention to the post and possibly compromise the confidentiality of their participation in the study. Some were concerned about parents asking questions about the content of a recorded delivery parcel. Women thought that it was acceptable to include a vaginal swab only in the kit rather than providing a choice between a swab or a urine sample, partly because it was what they were used to doing at the clinic.

Final follow-up procedures

The results of steps 1–3 informed the final follow-up procedures.

Key findings

We have described the stepwise approach that we used to develop our follow-up procedures for this trial.

The approach involved using evidence-based methods to increase follow-up, testing prototype procedures and obtaining potential participant views on the procedures.

Strengths and limitations

To the best of our knowledge this is the first description of a systematic approach to developing follow-up procedures. The approach has resulted in a follow-up package. In the single case study of our pilot trial it will not be possible to determine the effectiveness of the ‘follow-up package’ in isolation from other factors such as the management style and experience of the CTU and researchers conducting the pilot trial. It is not possible to determine which elements of the follow-up package are most important.

Discussion in relation to the existing literature

The approach mirrors methods used to develop behaviour change interventions, for example consulting with the user group, identifying barriers to performing behaviours and choosing techniques to enable the behaviours. 30,46 We used a similar approach to the approach used to develop follow-up procedures in the txt2stop pilot and main trial. The pilot trial achieved a 96% response rate for self-reported data collected by mobile phone or e-mail at 1 month and a 92% response rate at 6 months. 13 The main trial achieved a 95% (5524/5800) response rate for self-reported data collected by post, mobile phone or study website at 6 months and an 81% (542/666) response rate for postal salivary cotinine tests at 6 months. 10 An earlier trial achieved only a 74% response rate for self-reported data collected using voice and text messaging at 6 months and experienced differential follow-up between the intervention group and the control group (69% in the intervention group and 79% in the control group). 47

Implications for this research project

The follow-up procedures that we developed were used in the pilot trial (see Chapter 4).

Description of trial design

This was a pilot, parallel-arm randomised controlled trial with an allocation ratio of 1 : 1, conducted in multi-geographical areas of the UK.

Important changes to methods after trial commencement

There were no changes to the methods after the trial commenced.

Eligibility criteria for participants

People aged 16–24 years with a positive chlamydia test result or who had had unsafe sex in the last year (defined as more than one partner and at least one occasion of sex without a condom) and who owned a mobile phone were eligible. People who satisfied these requirements were ineligible if they were non-English-language speakers or were unable to provide informed consent (e.g. people with severe learning difficulties).

Settings and locations where the data were collected

This trial identified potential participants through sexual health services in six geographical locations in the UK: London, Cambridgeshire (rural and urban), Manchester, East Anglia, Kent and Hull. Research staff recruited participants on site at the London and Manchester services. Staff at the Cambridgeshire, East Anglia, Kent and Hull services identified eligible potential participants and referred them to the trial centre (LSHTM) for recruitment.

Intervention delivery and timing

The bespoke texting software delivered the intervention messages automatically, directly to the mobile phone number given by each participant at enrolment. The messages were tailored according to sex and infection status at enrolment. Additional tailoring enabled participants to choose a daily time period when they did not want the messages delivered (‘embargoed time’). We collected embargoed time preference data at enrolment, which were automatically fed into the texting software during baseline data entry (see Data collection and entry). The automatic embargoed time was from 2300 to 0900. Each day, the system delivered the messages from the start of the non-embargoed period, every 4 hours. For shorter non-embargoed periods, the system delivered the messages in proportionally shorter intervals. The computer automated mode of delivery ensured standardisation of the intervention.

Message frequency and spacing

For men and women testing positive for chlamydia the intervention included four messages per day for the first 3 days, reducing to one to two messages per day for the first 2 weeks. The number of messages was then reduced to one per day for the first month followed by between one and nine per month until 12 months. For men and women who tested negative for chlamydia the intervention included one to two messages per day for 1 month and then one to three messages per week for up to 12 months.

Intervention for chlamydia-, non-specific-urethritis- and gonorrhoea-positive participants

The intervention for female participants who received a chlamydia-, NSU- and gonorrhoea-positive result at the time of enrolment (‘positive participants’) consisted of 63 text messages sent over 1 year, starting from the point of randomisation. The intervention for positive male participants consisted of 61 text messages sent over 1 year, starting from the point of randomisation.

The message set was tailored according to sex and infection status at enrolment (no infection, chlamydia, gonorrhoea or NSU). The message sets for those diagnosed with a STI were similar to each other, except that the information provided was specific to the STI diagnosed. The numbers of messages targeting each behaviour and the numbers of messages employing specific intervention functions and BCTs are described in Table 6.

For those diagnosed with a STI, messages over the first 3 days focused on engaging with the study, getting treatment, taking treatment and providing information about the infection. Over the next week messages targeted telling partner(s) about an infection. The messages provided non-judgemental, non-stigmatising information covering how common infections are, that an individual may not have symptoms and so therefore be unaware that they have a STI; that many people diagnosed with a STI have had only one sexual partner in the previous year, and that infections are easy to treat. Messages provided information about how to prevent infections. They also provided suggestions about when, where and how to tell a partner about an infection and examples of how others had told partners, covering a range of different types of relationship (e.g. casual, long term). The messages then provided links to services that could inform partners and links to support for anyone concerned about violence in their relationship after telling a partner about an infection. Messages also aimed to provide social support, acknowledging people’s experiences.

For those diagnosed with an infection, after day 14 the messages targeted condom use and testing for STIs before having unprotected sex with a new partner, employing the same messages as for those who were not diagnosed with an infection.

Intervention for chlamydia-, non-specific-urethritis- and gonorrhoea-negative participants

The intervention for female participants who did not have a positive test result at the time of enrolment (‘negative participants’) consisted of 51 text messages, starting from the point of randomisation (see Table 6). The intervention for negative male participants consisted of 49 text messages, starting from the point of randomisation. Participants who had not been diagnosed with an infection were sent the messages about safer sexual behaviours (condom use and testing for STI) starting on day 1. Over the following 30 days messages were sent providing information on how to prevent infections and how you cannot assess risk according to how well you know someone or by their appearance. Messages included instructions on how to use condoms, emphasised positive aspects of condom use and provided tips on preventing condom problems and examples of how others resolved condom use problems. Participants were prompted to think about risks that they had taken and what they could do differently in the future and also to consider how they had carried out safer sexual behaviours in the past. Text messages included advice regarding getting tested before unprotected sex with a new partner. Participants were also sent links to further web-based information regarding contraception, alcohol and sexual risk, how to use a condom and general communication about sex. Women were sent messages covering how other women had negotiated condom use. The messages were designed to provide social support for safer sexual behaviours.

Primary outcomes

The primary outcomes for the pilot trial were the recruitment rates and completeness of follow-up for the proposed primary outcome for the main trial (cumulative incidence of STIs at 12 months).

Our target was to recruit 200 participants over 3 months and to achieve an 80% response rate at each follow-up point. We assessed the numbers recruited by the number randomised during the 3-month time period. We assessed the follow-up response by the numbers completing the questionnaire at months 1 and 12 and returning a chlamydia test sample at months 3 and 12.

Secondary outcomes

Secondary outcomes were:

• the proportion of messages successfully delivered (measured using the IT system metrics)

• at month 1 we assessed:

  • process outcomes:

    • number of text messages read (all/some/none)

    • Knowledge of someone else who took part in the study (yes/no) – if yes: if the other person read the messages we sent the participant; how many they read; if the participant read the messages we sent the other person and how many they read

    • If anyone read messages sent to the participant and if yes, how the participant felt about this

  • behavioural outcomes:

    • for participants testing positive for chlamydia, gonorrhoea or NSU at the time of recruitment: if they took the treatment (yes/no); if they avoided sex for 7 days after treatment (yes/no/unsure); if they told the last person they had sex with before the test that they needed to get treatment (yes/no/sort of); if they avoided sex with this person for 7 days after they took the treatment (yes/no/not applicable); and if there was someone else they were having sex with around the time they tested positive, if they told this person to get treatment (yes/no/there wasn’t anyone else)

    • condom use at last sex (yes/no/unsure)

    • sex with someone new since joining the study (yes/no/unsure)

    • condom use at last sex with someone new (yes/no/unsure)

    • STI testing for self prior to sex with someone new (yes/no/unsure)

    • participant’s report whether their last new partner was tested for STIs prior to sex with them (yes/no/unsure)

    • number of sexual partners since joining the study (0/1/2+)

• at month 3 we assessed:

  • infection (urine test for men and self-taken vulvovaginal swab for women, according to their preference) (positive/negative)

• at month 12 we assessed:

  • infection (urine test for men and self-taken vulvovaginal swab for women, according to their preference) (positive/negative)

  • behavioural outcomes:

    • for participants testing positive for chlamydia, gonorrhoea or NSU after joining the study: if they took the treatment (yes/no); if they avoided sex for 7 days after treatment (yes/no/unsure); if they told the last person they had sex with before the test that they needed to get treatment (yes/no/sort of); if they avoided sex with this person for 7 days after they took the treatment (yes/no/not applicable); and if there was someone else they were having sex with around the time they tested positive, if they told this person to get treatment (yes/no/there wasn’t anyone else)

    • condom use at last sex (yes/no/unsure)

    • sex with someone new since joining the study (yes/no/unsure)

    • condom use at last sex with someone new (yes/no/unsure)

    • STI testing for self prior to sex with someone new (yes/no/unsure)

    • participant’s report whether their last new partner was tested for STIs prior to sex with them (yes/no/unsure)

    • number of sexual partners since joining the study (0/1/2+)

    • number of text messages read (all/some/none)

    • car accident in which the participant was the driver in the past 12 months (yes/no).

We also report participants’ views regarding the intervention messages (agree/unsure/disagree):

• the text messages made me take action

• the text messages made me think

• the text messages were from someone I could trust

• the text messages were respectful

• the text messages talked down to me

• the text messages were easy to understand

• there were too few text messages each day

• there were too many text messages each day

• I would have liked the text messages to stop sooner

• the text messages came at the right time of day.

There were no changes to the trial outcomes after the trial commenced.

Sequence generation

An independent online randomisation system [see www.sealedenvelope.com/ (accessed 22 July 2016)] generated the 1 : 1 allocation sequence, stratified by site, using random permuted block sizes of 2, 4 and 6. Staff were not aware of the block sizes.

Allocation concealment

The online randomisation system generated the allocation sequence, which meant that staff enrolling participants into the trial could not have known in advance which treatment allocation the next participant would receive.

Implementation

The online randomisation system randomised participants immediately after the recruiting staff entered their baseline data onto the online trial database system (see Recruitment and Data collection and entry).

Masking

Because of the nature of the intervention, participants could have been aware of their treatment allocation; they would have expected frequent text messages (intervention) or one text message a month (control). Thus, the participants were unmasked. The trial manager (OM) required access to treatment allocation to monitor the incoming texts and identify intervention participants for the qualitative interviews. However, the risk of bias associated with this unmasking is low as the intervention was prescribed and delivered by the bespoke texting software, directly to participants’ mobile phones; OM was not involved in the delivery of the intervention. Laboratory staff assessing chlamydia infection and researchers assessing the outcomes were masked to treatment allocation. Staff performing the statistical analysis were also masked to treatment allocation. Data were double entered with one researcher masked to allocation. The treatment allocation variable in the data set was coded 1 or 2 and this was kept undisclosed until the full analysis was complete.

Pooling of sites

Data were pooled across all sources of recruitment.

Time points for analysis

This is a behavioural intervention unlikely to produce adverse effects and so the analysis by the research team was undertaken once, at the end of the trial and after the data set had been locked.

Methods for dealing with missing data

We conducted a complete-case analysis only.

Adjustments for covariates

We did not adjust for covariates in the primary analysis.

Multiple comparisons

We did not adjust for multiple comparisons.

Examination of subgroups

We did not conduct a subgroup analysis.

Analysis of primary and secondary end points

The primary outcomes were the recruitment rate and completeness of follow-up for the proposed primary outcome for the main trial and the proportion of messages successfully delivered to participants’ mobile phones. We report the cumulative incidence rate of chlamydia infection in the control group to inform the sample size calculation for the main trial. For each binary outcome we report relative risks with 95% CIs and give a two-sided p-value for statistical significance.

Adverse events

Involvement in a road traffic accident is the only plausible adverse event that might be caused by a mobile phone-based texting intervention. We also report the proportion of participants who experienced someone else reading their text messages and the participants’ response to this (happy/unhappy/unsure).

Primary outcomes

Our primary outcomes were full recruitment within 3 months and follow-up rate for our proposed primary outcome for the main trial. We fully recruited within 3 months and 97% of messages were successfully delivered. We obtained an 81.0% (162/200) follow-up rate for the cumulative incidence rate of chlamydia, with a rate of 81.2% (82/101) in the control group and 80.8% (80/99) in the intervention group (Table 8).

In total, 92% (183/200) provided questionnaire outcome data at 1 month. Of the 183 providing data, 80% (146/183) returned the postal questionnaire, 13% (23/183) completed the questionnaire online, 4% (7/183) completed the questionnaire at the clinic, 0.5% (1/183) responded to the key questions by e-mail and 3% (6/183) responded to the key questions by text message. In total, 86% (171/200) provided a chlamydia test sample at 3 months. Of the 171, 98% (167/171) returned the sample by post and 2% (4/200) provided the sample at the clinic. In total, 82% (163/200) provided questionnaire outcome data at 12 months. Of the 163, 94% (153/163) returned the postal questionnaire, 3% (5/163) completed the questionnaire online, 2% (3/163) completed the questionnaire at the clinic, 0% (0/163) responded to the key questions by e-mail and 1% (2/163) responded to the key questions by text message. Finally, 80% (160/200) provided a chlamydia test sample at 12 months (see Table 8). Of the 160, 98% (157/160) returned the sample by post and 2% (3/160) provided the sample at the clinic.

Secondary outcomes

Key findings

The pilot trial demonstrated the feasibility of the trial procedures for a main trial. We fully recruited early and achieved an 81% follow-up rate for our proposed primary outcome of cumulative incidence of chlamydia at 12 months. There was no differential follow-up between groups. The IT system delivering the messages was effective, with 97% of messages sent being successfully delivered to participants’ mobile phones. Participant views of the intervention suggest that it is acceptable to the majority of participants. Some participants shared messages with friends and there were three cases of control group participants (3%) reporting reading other participants’ messages.

Strengths and weakness

In the pilot trial we achieved a high follow-up rate, allocation was concealed and laboratory staff and those analysing data were blind to allocation. Only one of the researchers double entering data was masked to allocation; however, in a main trial there would be sufficient staff for all staff entering follow-up data to be masked to allocation. Given the small sample size and the large number of variables assessed, the baseline characteristics of participants were reasonably well balanced. There were some differences in baseline infections and ethnicity between groups. Nonetheless, as the primary outcomes for the pilot were recruitment and follow-up, the allocation balance would not impact on this. Although the response rate overall was high, the response rate for some questions, such as partner notification, was low. A larger sample size in a main trial would allow for better balance between the arms. The pilot trial was not powered for behavioural or STI outcomes and so 95% CIs for these outcomes were large and it is unsurprising that no outcomes were statistically significant when the multiple comparisons were taken into account.

Discussion in relation to the existing literature

This pilot trial’s follow-up response rate for return of the chlamydia test samples was considerably higher that that seen in similar trials, screening initiatives and surveys. 37 The Natsal study in the UK achieved a 57.7% response rate for face-to-face interviews and a 60% response rate for urine samples requested. 35 The ClaSS project reported an uptake of chlamydia postal screening of 31.5% in people aged 16–24 years,36 whereas the Sexunzipped trial achieved a 45% follow-up rate using chlamydia postal test kits and a 72% follow-up rate for self-reported data at 3 months. 37

The ClaSS project36 employed some elements of our approach to follow-up described in Chapter 3, such as choosing a postal testing kit that fit through a ‘standard’ letterbox and testing the kit with the target group. 48 In the ClaSS project the researchers evaluated interventions to increase follow-up after the project commenced and later adopted pre-notification in the form of an invitation letter sent in advance of the kits. Adopting our approach would have identified methods known to increase postal follow-up before the study commenced, which may have increased the response. Our response rate may be higher than that achieved by the ClaSS project because our participants had agreed to provide follow-up data when they were recruited, we offered unconditional incentives and we included only essential test kit components.

Generalisability

The pilot trial was designed to demonstrate the feasibility of a main trial. It was not designed to generate reliable estimates of the intervention effect and thus the intervention effects are neither accurately estimated nor generalisable. The proportion of eligible participants agreeing to take part was 66% (200/301). The intervention has been designed to be accessible across socioeconomic and ethnic groups.

The implications of the pilot trial results for the design of the main trial are discussed in Chapter 6.

Interviews

Qualitative interviews were conducted by RF with 20 participants by telephone 2–3 weeks after enrolment to the pilot trial. One interview was conducted by OM. Interviews took place between October 2013 and January 2014. The interviews followed a semistructured topic guide, which aimed to find out about participants’ views and experiences of the intervention and their recommendations for improvements. Questions were included on the tone and frequency of the text messages, the message content and sexual behaviour since enrolment, such as condom use and partner notification. Participants were each given £20 for completing the interview. The interviews were audio recorded and transcribed verbatim.

Follow-up interviews

Follow-up interviews with participants were conducted by OM after sending the 3-month postal test kits, asking for participants’ views on the acceptability of the follow-up materials and procedures. We interviewed 17 of the original 20 participants (we were unable to reach three participants). The follow-up interviews followed a semistructured topic guide, which explored participants’ views on the trial materials and follow-up procedure.

Thematic analysis

Data were managed and transcripts coded thematically using NVivo 10 (QSR International, Warrington, UK). After familiarisation with the data, RF generated an initial coding framework (with OM). RF coded all of the interviews according to the framework and these were checked by and agreed with CF. Each theme was described and subthemes identified by RF and CF. RF searched for deviant or atypical cases.

Engagement with text messages

Most young people were positive about the intervention. Five key themes relating to user engagement with the text messages were identified: the importance of tone, the frequency and timing of texts, convenience, saving messages for reflection and the sharing of messages.

Impact on knowledge

Topics reported to be particularly helpful included how to put a condom on, how to prevent condom breakages (e.g. not using oil-based lubricants), STI testing and how to talk to a partner as well as building confidence and reducing the stigma and worry related to the chlamydia test result.

Participants’ reports regarding the impact of the intervention on knowledge varied. At one end of the spectrum there were those who reported that they knew little about STIs or how to use a condom:

Well, there was this one, yeah, that said how to put a condom on, the best . . . [laughs]. The quick and fresh way to put a condom on . . . [laughs]. Because I didn’t know that much about condoms so I followed the link [to obtain further information] and I’m like, oh and it feels good when I learned how to put it on, you don’t have to use something that got oil, yeah, you don’t have to use it because the condom might burst and something like that . . . oh I didn’t know that’s how you get it [chlamydia], I didn’t know, I was like, oh I need to be more careful then, I need to use a condom mostly when I meet someone new.

ID01002, female, 23 years, intervention, chlamydia positive

Although some of the participants reported that they already knew most of the information, they said that the messages reminded them of what they had learnt in the past, reinforced this information or helped them reflect on what they knew:

Most of the stuff I knew but it kind of gave me a thought, because you don’t really think about it sometimes at the time that you’re getting into anything, you just kind of do what you’re doing, but because of the texts it kind of keeps it in your mind so you know what you’re doing really before you get into anything.

ID01043, male, 18 years, intervention, chlamydia negative

I think everyone should have this texting thing come out to them every day because sometimes you do forget little things that obviously you should be doing.

ID03013, female, 22 years, intervention, chlamydia positive

Some participants had not found the texts helpful, describing the messages as ‘common sense’. They tended to be older and/or chlamydia negative at enrolment. However, they generally felt that the advice was good but would be better targeted at those aged 16–18 years. Participants had the option to text ‘Stop’ if they wanted to discontinue receiving the messages. One had done this and he explained that he would have preferred more ‘scary facts . . . to make kids think’ (ID01042, male, 22 years, intervention, chlamydia negative). One of the female participants who had sexual relationships solely with women felt that some of the messages, for example those on condom use and contraception, were not relevant for her.

Reported impact on behaviour

Mechanism of action

Coding and analysing the interviews led to the development of a theoretical framework for the mechanism of action, that is, how the intervention is hypothesised to work at increasing safer sexual behaviours. Figure 2 illustrates the prerequisites for content and delivery and the mechanism of action. The findings from the interviews suggest that the intervention could work by providing information and skills to young people via a channel that is convenient and acceptable to them. For example, the texts appeared to help by providing new knowledge on how to put a condom on or facilitating condom use and breaking down assumptions about how chlamydia infection is transmitted. The messages could also work by allowing recipients to reflect on their behaviour and/or by helping them talk to their partner about the importance of protecting themselves against STIs, such as giving them the words that could be used when having these discussions or sharing the actual texts. The fact that this was done in a way that reduced stigma and was not pressured or judgemental assisted in communication with others.

FIGURE 2.

Prerequisites and mechanism of action from participants’ perspectives.

There was less suggestion from the interviews that attitudes had shifted. The one exception was in relation to stigma. Stigma associated with STIs can result in young people not accessing appropriate care and services16 and therefore its inclusion in health promotion interventions addressing sexual health is key.

Follow-up interviews

In total, 17 of the original 20 main trial interview participants (we were unable to reach three) were interviewed by OM. The participants found the materials and the procedure acceptable and none had any significant criticisms. They thought that the pre-notification served as a reminder to look in the post for the materials:

Yeah, definitely, it reminded you to look at your post I guess, yeah. Otherwise it tends to just pile up at our house, so it was better.

ID01005, female, 21 years, intervention, chlamydia negative

Similarly, participants mentioned that the blue envelopes helped them recognise that the contents were study materials and did not call attention to what was in them:

Yeah, I thought that was, it was fine, it’s like it’s not got anything suspicious you wouldn’t even think that there was a chlamydia test in there.

ID01067, female, 18 years, intervention, chlamydia negative

One participant said that the letters were polite in that we were not telling participants that they had to send back the tests and questionnaires and another appreciated that they were short and to the point:

They were clear as well, yeah, it’s like really, they were like really polite as well so it’s not just like, it’s telling you, you have to do it, like it’s speaking to you like an actual person so.

ID03003, female, 20 years, intervention, chlamydia positive

Most participants thought that the test instructions were clear and easy to follow and most did not have any problems or criticisms of the postal testing kit. One participant said that he initially was not clear whether or not he should post the box on its own:

No, about right, kind of not too informative but what you need to know, but when I received the test I can’t lie to you, like that was over in there and I was thinking, okay, I’ll follow the instructions but I was thinking, do I just send it in the box, or do I have to wait for something else to send it, put a stamp on it or something but then I thought, then I just thought yeah I think it’s just a box, I just put that in the postbox.

ID01043, male, 18 years, intervention, chlamydia negative

Another participant said it would have been easier if we had provided a pouch to collect the urine to pour it into the tube. One participant said that initially she had had difficulty opening the swab but worked it out. Another suggested that we include a condom in the kit.

Most participants said that they would have returned the questionnaire and chlamydia sample whether they were offered an incentive or not, with some indicating that the motivating factor was their health, not the money:

like obviously I was happy to receive it, like for doing the minimal thing, like I piss every day, you know . . . It was piss in a pot and you get twenty pound for it, obviously I was happy to receive it but it wasn’t really, it wasn’t really.

ID01042, male, 22 years, intervention, chlamydia negative

the test is like your health so you’re going to do it anyway.

ID03009, male, 20 years, control, chlamydia positive

A few participants mentioned that the unconditional £5 motivated them to return the questionnaire and test kit and another wanted to return them because we ‘treated’ him and said that he would have procrastinated without it. Women preferred the swab sample collection method and none of the participants mentioned that they would rather have had a choice of test (swab or urine).

Principal findings

The majority of young people who we interviewed were positive about the mobile phone texting intervention to promote safer sex, particularly as it was convenient and took little of their time. The frequency, timing and tone of the texts were appropriate for most. Receiving information and support in simple ‘bite-size’ messages was reported to help participants retain information. The text message medium also enabled participants to save and reflect on messages in their own time and share messages. Sharing texts provided participants with the opportunity to ‘educate’ friends and siblings and acted as a prompt for discussions about sexual health and safer sex behaviours with partners. Text messages reportedly improved knowledge and confidence and had a positive effect on safer sex behaviours, including condom use, STI testing and notification of partners about a positive STI test result and/or hastening notification of partners. Participants were happy with the follow-up procedures used, although there were a couple of suggestions regarding adding back in package content that we had removed to simplify follow-up procedures.

Strengths and weaknesses of the qualitative interviews

As far as we are aware this is the first study to describe recipients’ perspectives on how the mode of text messaging facilitated communication about sexual health. The nature of the short content and method of delivery may have made the messages more acceptable than traditional methods of health promotion such as printed leaflets. The content was designed to address attitudes, information and behaviour skills, rather than induce fear, which has been found to be ineffective. 10,17,18 The formative work carried out with the target group on the development of the messages was key to the intervention’s acceptability. Interviews were conducted shortly after participants had received the messages to minimise problems with recall. Our sampling strategy ensured that there was representation of different age groups, sexes and settings, so that a broad range of views could be included.

There are challenges in conducting research by telephone, for example telephone interviewing may have resulted in more superficial and briefer responses to questions than would have been the case if the interviews had been conducted face to face. 49 However, given the nature of the intervention this was an appropriate method that allowed us to interview geographically dispersed individuals. We were reliant on young people’s self-reports, which may differ from actual behaviour, and we were unable to explore the extent to which any behaviour change might be sustained. Young people may have provided responses that they felt would be desirable for the interviewer to hear and they may have also felt that they needed to be positive about the intervention itself. We tried to minimise this effect by having a member of the team (RF) conduct the interviews who was not directly involved with recruiting participants or the day-to-day running of the project.

Discussion of qualitative interviews in relation to the existing literature

In keeping with other research, participants viewed the mobile phone as an essential everyday item that is owned by most people, with easy-to-use technology. 19,20 The fact that messages are sent to participants rather than retrieved by them20 makes this a convenient, low-commitment way to receive and share information and gain support. The ‘always on you’ nature of the mobile phone21,22 enabled the mobile phone and the text messages to act as reminders and maintain the salience of sexual health behaviours. This is consistent with previous work, which reported that text messages in a smoking cessation intervention acted as reminders and maintained the importance of quitting. 23 Previous research in sexual health has also reported that text messages provided and reminded people of information. 24 The technology allowed participants to easily retain messages. 25 This enabled recipients to absorb information at their own pace and refer back to messages and reflect on them in relation to their own experiences and behaviour. Rereading messages has been reported in previous research in which a text message intervention was used to support smoking cessation. 23 In this case rereading messages was used as a tool to sustain motivation for quitting rather than for reflecting on past and current behaviour. Retaining messages also facilitated discussions with friends and family and partners. Retained messages were shown to partners to support participants in negotiating condom use and in telling partners about being diagnosed with a STI. This is in keeping with previous research, which has reported that women receiving text messages regarding contraception retained and shared messages to initiate conversations with partners about contraception. 26 The perception of the mobile phone as a highly personal object,25,27 combined with messages written in a non-judgemental tone, may have underpinned participants’ experiences of the intervention as providing support and increasing confidence. As others have shown, concern about ‘reputation’ and perceived social expectations can inhibit communication50 but, by increasing confidence and allaying fears, our findings suggest that a text messaging intervention has the potential to provide young people with skills to overcome some of the barriers to partner notification.

The favourable reception of our text messaging intervention among the young people who we interviewed resonates with findings from qualitative studies in Australia and the USA, which have found that sexual health promotion interventions delivered by text messaging are an acceptable and convenient way to deliver potentially sensitive information and support to young people. 16,51 In accordance with our findings, they found that young people favoured simple messages, they reflected on the content and they shared messages with friends. The Australian study reported no change in condom use. 52

In summary, our qualitative research found that a mobile phone texting intervention was acceptable to young people and the interviews suggested that it helped promote safer sexual behaviours, including increased condom use and partner notification. No changes were made to the follow-up procedures based on these interviews.

Strengths and weaknesses of the intervention development work

Our work on intervention development has some weaknesses: although the content associated with increased self-reported condom use is known,28 it remains unclear which BCTs are associated with increased effectiveness in reducing STIs. We therefore included all of the BCTs in face-to-face interventions evaluated by randomised controlled trial and reporting reductions in STIs at follow-up. To develop an intervention that was acceptable we excluded content that participants found to be unacceptable or irrelevant. Some evidence-based BCTs were modified based on feedback from young people and the effectiveness of the ‘acceptable’ but modified content is not yet known.

Although the current intervention is tailored by infection status and sex, it is not tailored according to specific personal issues with regard to adopting safer sex behaviours. Thus, messages sent may not all be directly relevant to every participant. During the conduct of our work a new internationally agreed taxonomy of BCTs was published. We included BCTs defined according to an older taxonomy in our intervention but coded the final intervention using the new internationally agreed taxonomy. The intervention requires further adaptation to ensure that the content is appropriate for men who have sex with men and women who have sex with women. We have received funding from the NIHR for a main trial and are carrying out these adaptations prior to starting the main trial.

Strengths and weaknesses of the development of the follow-up procedures work

To the best of our knowledge this is the first description of a systematic approach to developing follow-up procedures. The approach has resulted in a follow-up package. In the single case study of our pilot trial it was not possible to determine the effectiveness of the ‘follow-up package’ in isolation from other factors such as the management style and experience of the CTU and researchers conducting the pilot trial. It was not possible to determine which elements of the follow-up package are most important.

Strengths and weakness of the pilot trial

In the pilot trial we achieved high follow-up rates, allocation was concealed and laboratory staff and those analysing data were blind to allocation. Only one of the researchers double entering data was masked to allocation, whereas in a main trial there would be sufficient staff for all staff entering follow-up data to be masked to allocation. Given the small sample size and the large number of variables assessed, the baseline characteristics of the participants were reasonably well balanced. There were some imbalances between groups in the baseline characteristics of participants (ethnicity and infection status at recruitment). Nonetheless, as the primary outcomes for the pilot were recruitment and follow-up, the allocation balance would not impact on this. Although the response rate overall was high, the response rate for some questions, such as partner notification, was low. A larger sample size in a main trial would allow for better balance between the arms. The pilot trial was not powered for behavioural or STI outcomes and so 95% CIs for these outcomes were large and it is unsurprising that no outcomes were statistically significant when the multiple comparisons were taken into account.

Potential implications for health care

The suggestion in our qualitative research is that the text messages had a positive effect on the promotion of safer sexual behaviours, particularly with reference to providing encouragement, support and skills relating to partner notification, with strong implications for infection control. Mathematic modelling suggests that the expected probability of chlamydial reinfection without partner notification is 19.4%; however, if a partner receives treatment within 3 days of the patient being treated this is reduced to 4.2%. 53 It is estimated that only around 40–60% of sexual contacts are notified by patient referral28,30 and so new strategies are needed to help improve the partner notification process. If the difficulties of notifying a partner can be lessened by giving young people the necessary skills to expedite the process, as described in our study, and reduce the time to treatment, the number of contacts informed through patient referral is likely to increase.

If our trial shows that the intervention is effective, it will be low cost and could be integrated with electronic systems so that it is automatically sent to patients when they receive their test results.

Implications of our research for the main trial

A number of factors have been identified in the pilot work that should influence the design of the intervention for the main trial and the design of the main trial.

Based on the findings from our qualitative research we have made changes to the intervention for the main trial. We have refined the message content so that it is relevant to men who have sex with men and women who have sex with women, for example by ensuring that pronouns used are gender neutral. We have included additional content providing examples of how others negotiated condom use in ongoing sexual relationships. We will include an option for more messages for those who want this and send additional messages regarding how to stop messages for those who would like to stop receiving messages.

A number of issues have informed the main trial design. There was a small amount of contamination (sharing messages) between the intervention group and the control group, which should be taken into account in the sample size calculation for the main trial. Only two of the infections at 12 months’ follow-up occurred in those who did not have an infection at baseline. Conducting a main trial including only those with an infection at the outset would provide a higher incidence of STIs at follow-up and allow for a smaller sample size than using the current inclusion criteria employed in the pilot trial. Our overall follow-up rate was high but the response rate to the question about partner notification was low. It may be that this question appeared to be optional as it was not relevant to all participants. In the main trial, a response to this question will be clearly requested from all participants and the main trial will also include an objective measure of partner notification. Services will search clinic records to identify whether named partners attended for treatment.

Digital technology is rapidly evolving and young people are often among the first to adopt new innovations and novel means of communication. Although young people continue to communicate by short written messages, these can now be delivered by instant messaging or by social media messaging as well as by text message. It is likely that novel means of delivering messages may be developed in the future. The way that messages are received (directly flashing up on the screen on a private device with the ability to reread content in your own time) is similar for text messages, instant messages and private social media messages. The NIHR has funded a main trial to reliably establish the effect of our safer sex intervention on STIs at 1 year. Our trial will reliably establish the effect of the written content of the intervention, which may in the future be delivered using different delivery mechanisms (instant messaging, private social media messaging).

Potential implications for other similar interventions

It is feasible for videos and other visual content to be delivered by mobile phone. We focused our intervention on written messages as in earlier pilot work employing videos (conducted prior to this research) we found that young people’s engagement with the video intervention was highly dependent on whether they related to the specific person (people) portrayed. This in turn depended on the style of clothes (and whether these were the very latest trends), accent, perceived socioeconomic background, gender and ethnicity of the person (people) involved. Thus, young people considered that video content went out of date rapidly, whereas written messages were not easily dated. We found that written content could be generated that was considered more socioeconomically, gender and ethnic group neutral. In our view the written content of the intervention would not need to be frequently updated, although checks would need to be carried out regularly to ensure that the links to websites provided remained current. Future research could consider using animated content in videos within interventions.

Our intervention and research focuses on high-risk groups attending services. We and other researchers have used text messages and social media to encourage high-risk groups to use existing and novel internet-based services. 16,54 In this research we have demonstrated that content delivered by IT targeting safer sex can be developed so that it is acceptable to young people. A range of social media and mobile IT could also be used to encourage high-risk people who are not currently service users to adopt safer sexual practices.

Protocol

The pilot trial protocol is in the appendices.

Published

French R, McCarthy O, Baraitser P, Wellings K, Bailey J, Free C. Young people’s views and experiences of a mobile phone texting intervention to promote safer sex behaviour. JMIR Mhealth Uhealth 2016:4;e26.

McCarthy O, French R, Roberts I, Free C. Simple steps to improve trial follow up procedures. Trials 2016;17:28.

Submitted

Burns K, Keating P, Free C. A systematic review of randomised control trials of sexual health interventions delivered by mobile technologies. BMC Public Health; submitted.

Free C, McCarthy O, French R, Devries K, Michie S, Wellings K, et al. Safetxt: The development of an intervention delivered by text message to increase safer sex behaviours. BMJ Open; submitted.

McCarthy O, French R, Baraitser P, Roberts I, Rathod S, Devries K, et al. Safetxt: a pilot randomised controlled trial of a mobile phone-based intervention to increase safer sex behaviours in young people. BMJ Open; submitted.