The Prevention of Delirium system of care for older patients admitted to hospital for emergency care: the POD research programme including feasibility RCT

Visits to Hospital Elder Life Program sites

Alongside the content review of the HELP protocols, and to examine delivery of the HELP in its real-life context, the research team, as part of the research plan, undertook a visit to HELP sites in the USA and Canada in the spring of 2010. We are grateful to Professor Sharon Inouye for organising this.

The Hospital Elder Life Program materials

We encountered some unforeseen difficulties with the HELP in relation to background intellectual property rights. The HELP materials were released under signed contract agreements; this restricted the extent to which we could share and discuss the detailed content with non-HELP sites. These difficulties did not compromise our programme of work. Positive solutions were arrived at through an iterative process of discussions among the central HELP team, research team, Programme Implementation Team, Programme Management Board, and empirical work and literature review. The resultant delirium prevention model drew on the HELP protocols and principles (with permission), but extended their applicability to an NHS context.

Workstreams 2–5: conceptual framework

We employed normalisation process theory (NPT)30,32 as a sensitising lens through which to explore knowledge and ward practices on delirium and delirium prevention. NPT focuses on microsocial processes that affect implementation of a practice (or technique) in an organisation or clinical setting. Normalisation refers to the work of individuals as they engage in activities and by which ‘it becomes routinely embedded in . . . already existing, socially patterned knowledge and practices’. 30 NPT postulates four generative mechanisms that operate individually and collectively to explicate how practices (interventions) are embedded and ‘normalised’ in routine care, namely coherence, cognitive participation, collective action and reflexive monitoring (Table 3).

Whereas NPT has been developed as a tool for examining implementation processes and to enhance understanding of the implementation ‘gap’ between research and practice, we employed it to build a picture of how delirium and delirium prevention were understood as meaningful by acute ward staff, and how the work that staff were routinely engaged in was relevant to prevention. The aim was to facilitate systematic consideration of the barriers to incorporating, and the implementation strategies necessary to incorporate, delirium prevention within existing acute service delivery. Specifically, we were interested in how the work of staff, individually and collectively, was conducted in respect of the tasks that reduced or conversely increased iatrogenic and modifiable risk factors for delirium among those who were most vulnerable. Although the value of NPT is its focus on individual and collective practices in specific settings, we were also interested in examining the wider contextual features of settings that might affect implementation. 33,34 Thus, although new practices are introduced into organisations that vary in their history, culture, learning climate and readiness for change,35,36 organisational policies and practices are located in and are shaped by national, political, economic and health policy contexts that, in combination, will affect implementation processes and outcomes. 34

Workstreams 2–5: data collection

Data collection was undertaken by members of the research team who were not connected with the clinical teams and involved multiple qualitative methods: facilitated workshops with development teams, collection of documents/records, one-to-one interviews and focus groups with multiple stakeholders, and observation of ward practices. Informed consent was obtained from participants.

Workshops

Three workshops with the three development teams, facilitated by the researchers, were conducted, as specified in the original proposal. With the consent of team members, an additional round of workshops was held to review/refine a model of prevention relevant to the NHS. Researchers and participants worked in tandem at the workshops to:

• explore what shaped staff knowledge (or lack of awareness) of delirium and delirium prevention

• consider barriers to and opportunities for introducing a ward-based delirium prevention programme

• consider which risk factors should be targeted

• assess current practice and what would need to change to implement such a programme.

We used the HELP protocols and NICE guidelines8 to frame discussions and to examine the feasibility of involving volunteers in delirium prevention. The starting points in framing the workshop discussions were, first, the HELP model (see Table 1), specifically around the feasibility of involving volunteers in delirium prevention, and then the NICE guidelines. 8 The NICE guidelines8 provided more up-to-date and UK-specific evidence about the nature and scope of interventions to prevent delirium, albeit with little focus on how to embed practice and organisational change. Each workshop lasted ≈ 2 hours. All were audio-recorded and transcribed. The average attendance (mean) across the four workshops was as follows: site 1, 10.5; site 2, 10.5; and site 3, 7.75 (see Report Supplementary Material 2).

Interviews, ward observations and collection of documents/records

Between workshops, multiple data collection methods [qualitative interviews, ward observation and collection of documents/records (Figure 2)] were employed, using NPT30,32 as a sensitising lens to explore knowledge and ward practices on delirium and delirium prevention. Specific objectives of data collection were to:

• garner a more detailed and nuanced picture of how delirium and delirium prevention were understood by staff (knowledge of delirium/delirium prevention)

• explore current ward routines and staff practices pertinent to the assessment of delirium risk and the delivery of a delirium prevention programme (what was the work, how did it get done and by whom)

• examine the nature of the patient journey from A&E to the receiving ward, and the potential for identifying the risk of delirium at each point in the journey (contextual factors affecting the work)

• consider the current usage pattern of volunteers on the wards and the opportunities for and barriers to involving them in enhancing routine care relating to delirium prevention tasks (potential for introducing, integrating and routinising new practices).

FIGURE 2.

Qualitative research and development process for WSs 2–5.

Workstreams 2–5: analysis

Workshop proceedings and interviews were audio-recorded, transcribed and anonymised; observational notes were written up in expanded, chronological form, and all data were inputted and stored in NVivo version 9 (QSR International, Warrington, UK). Analysis and data synthesis were ongoing and iterative. Each workshop involved feedback and discussion of emerging findings and implications from the empirical data, which, in turn, generated further data collection and review of evidence on implementation strategies (see Figure 2).

We used grounded theory strategies,37 such as open and focused coding and memos, constant comparison and search for negative cases, to develop categories, their constituent properties and the relationships between them. We compared and contrasted knowledge and practices relating to delirium and delirium prevention within and across wards, the professional and organisational factors that shaped them, and the consequences for service delivery. The findings and analysis led to the development of an integrated delirium prevention programme, iteratively elaborated and refined during delirium prevention development team workshops. The programme embraced intervention protocols, an implementation process and practice tools to enhance integration of delirium prevention into routine clinical practice.

Visits to Hospital Elder Life Program sites in the USA and Canada

Members of the research team visited the active HELP sites in four hospitals in the USA and Canada. We were able to discuss and witness how the HELP system of care was organised and delivered on the ground. Although presented in the literature as a protocolised intervention, it was evident from the visits that, like most complex interventions, the content and style of the HELP varied between sites. It was also apparent that a considerable infrastructure was required to support HELP delivery, for example recruitment and training of volunteers and elder-life specialist nurses. Moreover, we observed that the ward nurses, although appreciative of the HELP system of care, seemed to have little involvement in its delivery. Following the visit, the focus on adaptation of the HELP centred on the following question:

• Is it possible to provide an effective, integrated model of delirium prevention that minimises the need for additional staffing, but that creates a therapeutic care dynamic between ward staff, volunteers and relatives? That is, does the intervention have to be delivered by an interdisciplinary team assisted by volunteers as an addition to existing ward practice (as in the HELP model), or can it be developed as a system of care that engages staff and volunteers with relatives, as appropriate, to provide a model of enhanced care?

To explore this question, we examined the literature on implementation to identify what successfully contributes to embedding new practices/interventions in routine care and we reframed the work with development teams to consider NICE guidance8 alongside the HELP protocols.

Knowledge and awareness of delirium

Although knowledge of delirium and interest in enhancing practice to prevent it was a key motivating factor for geriatricians’ involvement in the research, awareness of delirium was more variable among other staff. Although junior doctors might be familiar with the term ‘delirium’ and knowledge-based understanding was seen to have improved among registrars specialising in the care of older people, there was less confidence that such knowledge was routinely translated into action to prevent delirium or manage it when it occurred. For nursing and therapy staff, delirium had not featured in their professional training. Among all staff, delirium and delirium prevention were not included as part of mandatory training or in-service education programmes. This was seen to reflect the low salience attached to delirium and delirium prevention in policy and practice, such that, unlike other aspects of acute care delivery such as falls and pressure sores, there were no specific protocols relating to it in any of the sites.

Nursing, therapy and care staff generally did not use the term ‘delirium’; instead, the term ‘confusion’ or ‘acute confusion’ was more typically employed, particularly on elderly care wards:

It’s just that perhaps they don’t recognise it as delirium . . . they don’t put a label on it.

Doctor

Whatever the term used, among these staff, delirium was primarily understood in its manifestation as a problem for ward management and in the disruption it caused for other patients. Thus, awareness (unprompted) was predominantly of hyperactive delirium that resulted in difficulties for staff from problematic behaviour such as aggression, agitation, shouting and wandering. There was acknowledgement that hypoactive delirium, resulting in withdrawn, lethargic behaviour, could easily be overlooked in an acute environment. Indeed, staff awareness and understanding of the experience of delirium from the perspective of patients and caregivers was prompted through presentation of the evidence by the research team, and patients’ and caregivers’ concrete accounts of specific episodes of delirium during the workshops.

How staff perceived the nature, impact and consequences of the ‘problem’ of delirium affected how they sought to manage it. Awareness of ‘acute’ or ‘temporary’ confusion was seen to result in information-seeking from family and friends to determine whether this was of long-standing duration or of recent origin:

They might have been getting worse over a few weeks so, you really need to speak to a carer or relative; quite often we ring home care as well. We ring district nurses: ‘How are they normally? How have they been? Have you noticed any change in their condition over the last few weeks?’ . . . often the consultant . . . if we haven’t done it, will ask for us to get information from home care or whatever.

Senior nurse

Ascertaining that the change was recent and that the behaviour was atypical might precipitate a search for underlying causative factors contributory to the delirium (e.g. sepsis on elderly care wards), so as to identify solutions to address them (e.g. pain relief following surgery on orthopaedic wards). The practice consequences of identifying delirium also highlighted the process whereby delirium affects treatment and extends inpatient stay. Therapists, for example, indicated that mobilisation might need to be delayed to allow patients the chance to recover sufficiently to engage in rehabilitation:

That’s very common [delirium with sepsis], now those patients who are . . . acutely ill and we feel are in that stage, we don’t always try and do anything with them in the early days because we’re aware of the fact that, say they’d come in with a UTI [urinary tract infection] that, sometimes, just having a couple of days to recuperate means that, when we intervene, then they’ll have a much more successful outcome . . . they’re the sort of patients who we might discuss with the nursing staff and they’ll say, ‘leave it today’, you know . . .

Therapist

Some staff used the terms ‘confusion’ and ‘acute confusion’ interchangeably. This imprecision in language use denoted a lack of clarity about the distinction between acute confusion and dementia. The practice consequence was that search for a cause might not be pursued:

I think a lot of the times . . . it’s probably put down more to dementia than it is to delirium . . . when, I guess, so many people who have dementia are . . . more susceptible to having delirium . . . And then [for people with dementia], I think it’s probably more put down to: ‘they’re . . . out of their own environment, they’ve had a traumatic operation, they’re just more confused’, rather than there’s perhaps another underlying issue that’s causing it . . .

Therapist

The conflation of delirium and dementia by staff was a source of heightened anxiety and perplexity among caregivers/relatives, as the suddenness of the change and the strangeness of the behaviour of their relative was not understood by staff. Aggression and/or refusal to participate in treatment could be interpreted as ‘lack of engagement’, resulting in the patient being perceived as unsuitable for rehabilitation or berated by staff for ‘inappropriate’ behaviour. The following is an illustrative example.

Mrs Patterson’s (a pseudonym) brother-in-law was admitted to hospital ‘with a very high temperature and inflammation in his leg. I’m not quite sure what diagnosis was put on it’. He was also disabled following a stroke several years previously:

When he was admitted . . . everything went . . . during the night he just screamed for my sister . . . I went down to the hospital the following morning . . . it was obvious to me something was wrong . . . he was shouting and aggressive . . . and demanding. The nurse said to me when I went on the ward: ‘Oh, I’m glad you’re here, I want to say this in front of you [looking at the brother-in-law] that you are a very difficult man and we don’t like the way you’re speaking to us and if you continue we will refuse to nurse you’ . . . I said to her that he’s not like this usually . . . The doctor later confirmed that he had delirium.

Mrs Patterson

Generally, then, variability in how delirium was understood among different groups of staff and the lack of investment at an organisational level in respect of training and education meant that, in NPT terms, delirium identification had low coherence. Delirium diagnosis was primarily effected through use of observational cues, although how these were interpreted and acted on depended on the expertise of those making the observations. Thus, management practices following on from observations reflected the skills and interests of individual professionals, rather than a collective staff and ward response.

Delirium prevention

Given the low coherence of delirium among staff groups across sites, it is hardly surprising that delirium prevention was not perceived as meaningful. Even when senior staff had initiated action to increase awareness of delirium risk (e.g. posters displaying risk factors), this did not inform assessment and care practices: ‘it’s not in the foreground of people’s minds’ (geriatrician). Interviews and observations indicated that knowledge of delirium among individual staff did not necessarily translate into specific beliefs and behaviours (cognitive participation) and the organisation of work practices geared towards prevention (collective action).

In one elderly care ward, we observed that senior nursing staff employed the term ‘delirium’ in describing specific patients, and demonstrated awareness and knowledge of both hypoactive and hyperactive delirium, as well as sensitivity to the distress caused to patients with it. The consultant geriatrician also had a particular interest in delirium. During observation of a nursing handover meeting on this ward, it was reported that just under one-fifth of current patients were characterised as having delirium. One of the patients with delirium discussed was perceived as needing considerable assistance with eating and drinking; another was referred to as having ‘hypoactive delirium’, ‘really drowsy’, not sufficiently alert to eat and drink, incontinent and ‘on IV [intravenous] fluids’. For the former patient, it was emphasised that all staff should be alerted to ensure support at mealtimes and to encourage drinking and eating. For the latter, it was agreed that she should be moved to a bed that was more visible from the nurses’ station, although this also provoked discussion about the disorientation such a move might cause. At the same meeting, several newly admitted patients were described as having symptoms that, to the observer, might portend risk of developing delirium: an 89-year-old patient who had experienced multiple urinary tract infections and been admitted following a fall, and an 80-year-old patient with a urine infection and pneumonia who had suffered a heart attack and needed oxygen. The symptoms were presented without reference to or discussion about delirium risk or any specific preventative action to be taken. This was recognised as typical practice by the development teams. Thus, even when there was shared understanding of delirium management, this did not facilitate noting and acting on risk factors before delirium had occurred (cognitive participation in NPT).

One exception to this general gap between knowledge and practice in delirium prevention was the development and implementation of a protocol on pain management post surgery for use in hip fracture patients on the trauma orthopaedic ward. This was aimed at delirium prevention. Staff remarked on how the protocol was routinely pursued, with positive outcomes as a consequence, particularly in reducing the severity and duration of delirium episodes. The ward manager attributed success to specific features of the hip fracture patient pathway: this was direct, linear and highly protocolised, with all patients diagnosed with hip fracture fast-tracked from the A&E department to the ward to undergo surgery within 24 hours. Insertion of the protocol into the pathway was viewed as an elaboration of existing practice, rather than as a major shift in how things were done. Practice change was reinforced by the perception among nursing staff that this was a relatively simple intervention with visible positive effect in a short period of time.

By contrast, the patient journey to elderly care wards across the three hospitals was more protracted and diverse. Triage systems and initial investigation in A&E to determine a differential diagnosis and whether or not admission was warranted might be followed by further observations in a short-stay assessment facility for up to 48 hours, which could be further protracted because of a shortage of acute ward beds. The chaotic nature of A&E and short-stay assessment facility environments, compounded by the multiple potential aetiologies of delirium in these settings, was viewed as contributing to delirium risk so that the scope for preventing incident delirium on acute wards could be adversely affected by the length of the patient journey into them. Even so, delirium prevention was considered to be feasible and worthwhile in the acute ward environment, although organisational factors shaping the patient journey through the hospital also needed attention as part of a strategic approach to prevention.

Current ward routines and practices

From interviews with staff and development team discussions, the acute care ward was reported as ‘busy’, often ‘chaotic’ and challenging: a picture reinforced by research observation. Explanatory, contributory factors offered by staff included patient mix and the policy and organisational imperative to achieve rapid patient throughput. Policy and service emphasis on hospital admission of those who required specialist medical and nursing expertise that could not be provided in alternative settings meant that patients were very acutely ill. Similarly, it was expected that patients would move on from acute care once medical and functional needs were met to secure ‘safe’ discharge. Patient moves within wards across all sites were also common, reflecting various organisational contingencies.

The hectic nature of ward life had the consequence that routine practice was described by staff as being primarily directed at responding to what was immediately presented, with priority given to diagnostic, observational and interdisciplinary assessment and care-planning. This picture was reinforced from observation. Thus, particularly for nursing and auxiliary staff, ward life was organised on the basis of a structured rhythm of time-sequenced care (washing, toileting), observations, diagnostic processes and treatment, punctuated by meals and visiting times, a pattern that was prone to disruption as a result of crisis events. Alongside this daily rhythm was the management of patient flow (admissions and discharges) and associated activities (negotiating with bed managers, discharge co-ordinators, social workers, relatives and community agencies), including record-keeping.

The variability and general understanding of delirium prevention among staff meant that it was not a significant driver of ward care practice. However, although delirium preventative interventions relate primarily to features of care quality, it is pertinent to consider how relevant routine care practices were accomplished, including the barriers and contextual factors that affected them.

Developing a model of delirium prevention

Within development teams, and through iterative feedback of empirical findings, we pursued in-depth discussion of the content of a multicomponent delirium prevention intervention and implementation process, with particular focus at the outset on the HELP mode of delivery. With regard to the intervention, there was consensus among the development teams that the NICE components and recommendations would constitute the content, as NICE extends the HELP intervention with up-to-date evidence.

One unique aspect of the HELP mode of delivery, as described previously, is the use of trained volunteers in assisting the HELP interdisciplinary team with some of the core interventions. Development teams perceived this feature of delivery as posing major practical and conceptual difficulties, thereby challenging its feasibility in an NHS context. Conceptually, although there was considerable enthusiasm for volunteer involvement, staff considered that ward practice in respect of delirium prevention activities was central to delivering consistent, quality care, such that staff needed to be actively involved in these activities. There was understanding among some senior staff that ward care practices such as nutrition, fluid intake and mobilisation were significant not only in helping to manage delirium, but in having a preventative effect on its development. These practices were also viewed as pertinent to other areas of prevention that have been targeted for action at national and local policy levels to secure care quality improvements, such as falls and pressure sores. Engaging staff in the work of delirium prevention, then, was viewed as enhancing staff awareness of and ascribing legitimacy to work that has a wide-spectrum preventative effect, with the potential to increase patient care quality overall.

Practically, the level of resource required to emulate the HELP was viewed by all of the development teams as unachievable because they believed that substantial additional staffing would be required to deliver the intervention to all patients on a typical elderly care ward. Consequently, in collaboration with the development teams, a model of delirium prevention evolved whereby the core components of prevention were assimilated into the daily routine of staff and volunteers without the need for additional staffing. This combined a practice change in the way staff went about their daily routines in respect of the 10 core components with an enhanced role for volunteers.

However, this presented two major challenges for implementation. First, there was the paucity of knowledge and understanding of delirium prevention, particularly among nursing and care staff, whose routine practices were critical in delivering preventative interventions. Second, the enthusiasm of ward staff for involving volunteers in a more focused and direct role with patients was seen to require considerable change in the way volunteers were currently deployed.

The development of such a model, therefore, required attention to both the processes and strategies for achieving practice change and the systems and mechanisms necessary to recruit, train and support volunteers to provide an enhanced and co-ordinated role in a whole-ward intervention. Such changes, moreover, had to flow directly from a knowledge and awareness of delirium prevention as worth the investment by staff individually and collectively. This represented a shift in direction from refining the HELP for an NHS context to developing a new model of delirium prevention, namely the POD system of care.

The programme we developed (the POD system of care) was the product of the interaction of the development teams’ practice knowledge, current best evidence on delirium prevention,8 and consideration of the findings of our empirical research and recent reviews of implementation theory and research. 29,30,38 The content and implementation process documented in the resultant system of care was then further tested and refined through dialogue with the development teams.

The Prevention of Delirium system of care interventions

The POD system of care interventions comprise actions encapsulated in protocols centring on 10 targeted clinical risk factors associated with the development of delirium among vulnerable patients. 8 The risk factors were organised hierarchically into three distinct delirium prevention ‘bundles’, according to a number of factors, including the level of expertise needed for their implementation; the bundles also provide a framework for ward staff to identify what should be done and by whom, taking into account local policies and practices:

1. Actions that might typically be carried out as part of existing medical/nursing roles (assessing and managing pain, medication management, hypoxia and infection management).

2. Actions that, depending on the level of patient need, might require skilled therapy/nursing and care input, at one end of the continuum, to, at the other end, assistance provided by volunteers with appropriate competencies (e.g. mobilisation, mealtime assistance).

3. Actions that offered scope for volunteers to enhance care practices while stimulating practice change towards providing holistic care to patients (engaging in social and stimulating activities for which volunteers can offer a unique contribution).

Prevention of Delirium system of care implementation process

The POD system of care implementation process incorporates systems and mechanisms aimed at introducing, embedding and sustaining the POD system of care interventions into routine ward care. It envisaged implementation as a process involving a number of steps, not just a single event. 38 These comprised (1) mobilisation of a staff action group, (2) staff (and volunteer) training, (3) review of current ward practice, (4) examination of delirium risk factors in relation to current ward practice, (5) implementation of delirium prevention practice and (6) the volunteer programme:

Patient description

Anonymous ward-level patient administrative system data (sex, age on admission, length of hospital stay and discharge destination) were obtained for all admissions during the implementation and delivery phases (see Report Supplementary Material 7).

Implementation planning and delivery

We undertook qualitative interviews using topic guides with staff and volunteers; informant interviews and conversations with implementation team members; observation of ward practices, multidisciplinary team (MDT) meetings, implementation team discussions and volunteer training sessions; and collection of documents (e.g. assessment, care and discharge plans; information for patients and caregivers; and care pathways). In addition, we constructed a ward diary/events log to provide a contemporaneous account of the process of implementing and delivering PODv1; communication with teams; problems encountered; solutions arrived at; and contextual factors that affected implementation planning and delivery.

To facilitate shared learning between sites, we arranged a centrally located workshop. This had a secondary purpose: to apprise the research team with information about how sites perceived the implementation and delivery processes. Only wards 1 and 2 had, at this point, begun delivery; wards 3 and 4 were in the early stages of implementation planning and ward 5 had not started implementation planning (ward 6 had not been recruited) (see Report Supplementary Material 6 for participants). The proceedings were audio-recorded.

Take-up of the intervention

We examined the extent to which each ward instigated systems to embed PODv1 in current ward practice. This included:

• the development and introduction of –

  • a system for identifying delirium risk

  • a daily delirium prevention plan

  • a volunteer care plan and a process for supporting volunteers

• audits and observations undertaken to assess/review current practice pertinent to the 10 delirium risk factors.

Impact of the intervention on nurse workload [wards 1–4 and 6 (implementation only)]

We used a ‘dependency–acuity–quality’ method at the start of POD implementation and during POD delivery to gauge its impact on ward staff activity and modification of workload. 48,49 This involved ward-based structured observations by researchers of staff activities linked to patients’ dependency/acuity. Activities included direct care (face-to-face bedside care), indirect care (patient-related, but not face-to-face, activity), associated work (e.g. ‘hotel’-type duties) and personal time (e.g. meal breaks). To obtain a broad sample of nurses’ workloads, we undertook ward observations over 24 hours during six shifts (two early, two late and two night shifts).

Impact on patient and carer satisfaction with care (wards 1–4 and 6)

We conducted a postal patient and carer satisfaction survey at baseline and during the delivery phase using relevant questions from the Care Quality Commission’s national patient survey instrument for patients50 and, for carers, a 19-item questionnaire. 51 Both were distributed by ward staff near discharge from hospital during both study periods.

Acceptability to patients, carers, staff and volunteers (wards 1–4 and 6)

We undertook interviews with a sample of staff, volunteers, patients and carers, and organised a workshop involving implementation team members from each participating site to share and reflect on implementation experiences.

Adherence to protocols

Adherence to the POD protocols in the four implementing sites was generally good: care plans for patients specifying action on each of the delirium risk factors were completed, integrated into patient notes as part of the admission process and reviewed in the MDT/ward round/handover, as necessary. Several sites developed new ways of responding to needs around communication and stimulation. For example, on ward 6, the senior occupational therapist involved occupational therapist students in engaging in therapeutic activities (reminiscence work, playing games) with patients identified as being at high risk of delirium. Occupational therapists also worked with volunteers to engage with patients based on information in the care plan on what interested them and relatives were encouraged to bring in patients’ favourite music and books. In one full implementation ward (ward 1), initial high adherence to protocols, as reflected in completion of care plans, reduced towards the end of the delivery period. Contextual factors were implicated. Early in the delivery phase, senior hospital managers conveyed their intention to close the ward as part of a strategy to reduce acute beds. The proposal was subsequently revised to merge ward 1 with an adjacent ward at the conclusion of the study, thereby effecting an overall reduction in bed capacity. However, a combination of the ward manager taking on responsibility for the two wards in the interim and uncertainty engendered among staff had the consequence that several staff moved to other posts and morale was adversely affected, which affected engagement with the research.

Changing ward practice

Similar to ward staff in the project 1 sites, nursing, therapy and care staff on all participating wards reported minimal knowledge of the significance of delirium and its adverse outcomes for patients and caregivers. In addition, there was little or no awareness that delirium might be prevented among those at risk. Education sessions, observation and structured review of current practice proved helpful and facilitated empathic connection with the experience of patients with delirium, as opposed to ‘just seeing a “problem” patient’ (sister, ward 1).

Senior ward staff in wards 1, 2, 3 and 6 and observation of practice suggested that, even prior to delivery, but during the implementation planning phase, engagement in the POD system of care had resulted in practice change:

Slowly you started noticing at handovers . . . that staff . . . wouldn’t say that Mrs X was confused, the word confused went, and people talked about whether she may have a delirium . . . it became a clinical thing, not something to be dismissed . . . and delirium wasn’t just about the person walking up and down . . . they were picking up on people who were quiet. They just started associating a sudden change in behaviour of patients with possible delirium and doing something about it.

Matron, wards 1 and 2

They also reported that, whereas before nursing and care staff might have reacted impatiently if a patient was ‘behaving badly’, now they were more patient and would spend time talking to the person, seeking to ease their confusion.

The period of implementation and delivery of the PODv1 was one of considerable organisational turbulence shaped by both national policy drivers (e.g. the imperative to achieve efficiency savings) and initiatives on improving care for people with dementia, and by local contextual factors such as ward re-organisations and staffing difficulties. This affected the engagement of the sites in both the implementation planning and delivery of the POD system of care.

Volunteers

Questionnaires: patient and carer satisfaction

Interviews with patients and carers

For the patients and carers that were interviewed (one patient, three carers and five patient/carer dyads), it was the focus of the POD interventions that was valued: attention given to hydration and nutrition, meeting sensory needs, and help with mobilisation. Particularly valued by carers was staff spending time with their relative and getting to know what was important to them. Carers’ main criticisms related to the communication of information, such as failure of staff to actively seek or regard information about the patient, lack of involvement in discharge planning and the unavailability of nursing staff. The small sample reflects recruitment difficulties. Ethics approvals did not permit us to have direct access to patients’ personal information. It was intended that a letter inviting participation with a stamped addressed reply envelope would be given out by staff at patient discharge. This did not happen consistently. The method of recruitment was also not conducive to engaging people, many of whom were frail and living with cognitive problems.

Ward staff

Staff found some aspects of the POD system of care challenging. Of particular issue were the volume and clarity of the POD manual and the time required to implement the system of care and to support volunteers. However, staff in the majority of sites believed that the POD system of care had been beneficial and had resulted in practice change. In some wards (wards 1, 2, 3 and 6), it was considered that the ward team had developed an increased understanding and recognition of delirium and that this had enhanced practice.

Staff accepted and appreciated volunteers and considered that they brought a new and positive dimension to the ward. There were some initial concerns on the part of staff regarding the tasks that volunteers would carry out and around issues of confidentiality. In practice, they found that their fears were unfounded. Staff valued having the consistency of regular volunteers who knew what was wanted of them. The general assessment by staff of the volunteers who sustained their involvement with the ward was that they were ‘very good’ or ‘excellent’. On only one ward (ward 3) were there concerns expressed about the calibre of volunteers, specifically of some student volunteers. In ward 6, by contrast, a collaborative initiative involving sixth-form colleges was very successful in engaging volunteers interested in pursuing careers in medicine, nursing and allied professions. Although slow to establish, this was pursued beyond the POD programme, recruiting a large volunteer team of young people, which was sustained through reciprocal support of ward staff and volunteers.

Volunteers

When interviewed about their experiences, volunteers reported that they had generally found staff to be friendly and welcoming, but were not always sure that they were valued by them. Most volunteers were initially anxious about their role and lacked confidence about how best to approach patients and had sometimes felt uncertain about what they should be doing. As noted previously, the early period was particularly vulnerable to volunteer attrition. In wards where support was perceived to be inadequate, those volunteers who continued often had previous experience of volunteering or working in a care environment. Volunteers who remained reported considerable pleasure and enjoyment in their work, even if it was regarded as emotionally difficult at times.

Significance of the early delivery phase

Although much attention is drawn in the implementation process and materials to engaging staff in practice change, the findings suggest that the early phase of delivery is also critical to continuance.

Volunteers

The model of delirium prevention that was adopted included a prominent role for hospital volunteers. However, most wards were not able to recruit or sustain the number of volunteers needed to have a major impact in PODv1 delivery. Therefore, a re-assessment of the role of volunteers in delirium prevention work on the ward was undertaken, preparatory to project 3.

Hospitals and wards

We aimed to recruit 16 wards in eight NHS hospitals in England and Wales: one elderly care and one orthopaedic trauma ward in each hospital.

The inclusion criteria for ward participation were the demonstration of adequate ward nurse staffing, as assessed against national guidance,56,57 and the agreed involvement of a named ward manager, a senior nurse and a VSM (if local staff intended to use voluntary services as a component of the intervention). In addition, there was a requirement for the equivalent of 1 day per week per ward of dedicated time for 3–4 months from an experienced senior nurse to lead the implementation.

Wards were excluded if they had previously participated in the development of the POD system of care or if they intended to implement other delirium prevention initiatives during the trial.

Participants

As the POD system of care is a whole-ward intervention, all patients in the ward (regardless of eligibility and consent status) would have the potential to be exposed to the intervention. Patients were therefore recruited for completion of individual outcome assessments only.

Patients aged ≥ 65 years who were admitted to the study wards during the study period were eligible for participation.

Patients were excluded if they had prevalent delirium on admission to the ward; if discharge was planned within 48 hours of admission; if a delirium assessment had not been performed by a research assistant (RA) within 24 hours of admission (elderly care patients) or preoperatively (orthopaedic trauma patients); if consent had not been obtained with 48 hours of admission to the ward; if end-of-life care was being provided; and if they had transferred from another ward or were not under the care of the ward team. Participants were recruited for 6 months following the 6-month intervention implementation period.

Primary outcome

We assessed for differences in new-onset delirium within 10 days of recruitment between patients in the intervention group (POD programme) and patients in the control group (usual care), as this is the expected primary outcome for a definitive trial. Delirium was assessed using the four-item Confusion Assessment Method (CAM)58,59 (Table 8).

Secondary outcomes

Physical and social independence were measured by the RAs at baseline and at 3 months (postal questionnaire) using the Nottingham Extended Activities of Daily Living (NEADL) scale;62 anxiety and depression were measured by the RA using the Clinical Anxiety Scale63 and the Geriatric Depression Scale Short Form,64 respectively, at 30 days.

Research assistant Confusion Assessment Method training

A CAM training and monitoring process was developed that followed recommended practices. 65 We developed a three-stage training process. Stage 1 was central or local classroom teaching about delirium, trial research procedures and the administration of outcome measurement instruments, including the CAM. Stage 2 was specific to the CAM and involved local experiential learning consisting of (1) one-to-one practice sessions, (2) pilot interviews with patients and (3) within-site inter-rater reliability assessments. Stage 3 was a further within-site inter-rater CAM reliability performance check conducted at the local sites. 59

Data collection

Data collection was undertaken by locally based RAs who were trained in study procedures and outcome measures.

Primary outcome

The RAs performed cognitive assessments [AMTS and months of the year backwards (MotYB) test] and the CAM daily for up to 10 days post recruitment (or until discharge, if sooner) to detect the presence of new delirium. Each CAM item was assessed and recorded on a clinical research form that was dated and signed. This document was stored digitally and accessed at a later date to investigate achievement of the completeness of the CAM assessments.

Discharge assessment

At the point of discharge, the RAs recorded the date of discharge (or date of death), episodes of falls in hospital and discharge destination (living alone, living with another person, residential care home, nursing home, other).

Thirty-day assessment

At 30 days post recruitment, the RAs performed a cognitive assessment (AMTS and MotYB test) and the CAM, and asked the patient to complete a questionnaire about health-related quality of life using the EQ-5D,68 about anxiety using the Clinical Anxiety Scale,63 about depression using the Geriatric Depression Scale Short Form64 and about patient experience using selected questions from the patient-reported experience measure from the National Audit of Intermediate Care. 69

Three-month assessment

At 3 months post recruitment, postal questionnaires were used to provide information on physical and social independence (NEADL scale),62 health-related quality of life (EQ-5D),68 and health and social care resource use and living arrangements. Proxy completion of the questionnaires was permitted.

Estimation of recruitment rates

We recorded the number of sites expressing an interest in participating in the trial and reasons for non-progression. To assess the feasibility of recruiting participants for a definitive trial, we calculated the number of patients screened, eligible, assessed for delirium, with prevalent delirium, with capacity to consent and for whom consent for trial participation was obtained. Baseline descriptors of the screened and recruited populations were obtained (see Characteristics of the screened and registered participants: generalisability) and compared between the groups to assess for imbalance.

Estimates of completeness of data collection and follow-up rates

The reliable calculation of delirium incidence rates requires close adherence to a predetermined delirium detection process. We therefore recorded the number of in-hospital delirium assessments and 30-day delirium assessments conducted, and calculated the missing observations. We also recorded the number and timing of participant withdrawals from follow-up data collection and the reasons for withdrawal (including deaths), and the number of participants with missing self-reported outcome questionnaires at each time point.

Assessment of between-ward intervention contamination

The number of staff moving on and off study wards within sites was collected for a sample period of 1 week. The number of participants moving wards during their hospital stay was tabulated. Incidence rates of new-onset delirium at the sites that were randomised at the hospital level were calculated and compared with those from sites that were randomised at the ward level, to assess possible between-ward contamination. Incidence rates of new-onset delirium were calculated for participants recruited within the first 3 months of sites opening to recruitment, and for participants recruited between 3 and 6 months of sites opening to recruitment to determine if the intervention delivery was sustained when more time had elapsed since initial training. Service improvements introduced on participating wards during the study period were recorded.

Estimation of a sample size for a future definitive randomised controlled trial

To inform the sample size calculation for a possible definitive trial, we calculated the incidence of new-onset delirium within 10 days of admission by ward type, by study arm and overall, together with corresponding 95% CIs. We used multilevel logistic regression that adjusted for demographic characteristics (age and sex), delirium risk factors (medications associated with delirium, e.g. benzodiazepines, opiates, H₁ antihistamines),75 sensory impairment (hearing impaired, use of hearing aid or sight impaired), cognitive impairment and/or dementia, Charlson Comorbidity Index,66 NEWS67 category and ward type. In the regression model, ward type was fitted as a random effect. The number of new patients admitted per ward during the recruitment period was used to estimate cluster size. The intracluster correlation coefficient (ICC) and associated 95% CI were calculated using the covariance parameter estimate from a multilevel logistic regression without adjustment for participant or ward characteristics.

Criteria for continuation to a future definitive randomised controlled trial

A priori criteria for progression to a definitive randomised controlled trial were defined as a minimum of six of the eight wards (75%) completing the POD manual milestone checklist (to provide assurance that the POD implementation was successful) and an overall recruitment rate of at least 10% of the potential recruitment pool. The criteria did not include thresholds for projected clinical effectiveness or cost-effectiveness.

Model development

To estimate the cost-effectiveness of an integrated delirium prevention intervention in the context of the trial, a decision-analytic model was used. The model was developed after consultation with the research team (including clinical experts) and the parameter values were identified following targeted searches of the literature. The working report describing the model development and results is included in Appendix 4.

Cost-effectiveness study

The aim of the economic study was to establish the feasibility of conducting an economic evaluation of the POD system of care and to determine preliminary estimates of its cost-effectiveness. Specific objectives were to:

• determine the feasibility of collecting the assessments needed (quality of life and health-care resource use) for an economic evaluation in this patient group

• determine the number of missing data in assessments

• determine the validity and responsiveness of quality-of-life assessments in this group

• determine the feasibility of collecting and of using/interpreting proxy-completed assessments

• estimate the cost of the POD intervention

• provide estimates of the cost-effectiveness of POD, compared with usual care

• compare these estimates with those from the earlier evaluation based on decision modelling.

Quality of life was assessed using the EQ-5D68 at baseline and at 1 and 3 months. Health-care resource use was captured using a specially designed questionnaire completed by patients (and/or proxies) at 3 months. Costs were calculated from the perspective of health services and Personal Social Services. The cost of the POD intervention was estimated to include material costs (e.g. printing of manuals), the time to deliver and receive the training and also the time to provide support during POD delivery. This information was provided by the POD research team, which kept a contemporaneous diary of visits and travel. The feasibility of data collection was determined by observing the extent of missing data.

The primary economic evaluation adopted the NICE-preferred approach of a cost–utility analysis comparing the costs and benefits of POD and usual care. 76 The analysis time horizon was 3 months, based on the trial follow-up. The main analysis result was the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY). ICERs below the range of £20,000–30,000 indicate that POD would be considered cost-effective. Non-parametric bootstrapping was employed to determine the level of sampling uncertainty. No discounting of costs or effects was conducted.

See Appendix 5 for full details of the methods.

Hospitals and wards

Twenty hospitals expressed interest. Twelve hospitals subsequently completed and returned site survey forms, and eight of these were recruited. Among the four hospitals not recruited, two withdrew (one because of poor staffing and one was unable to identify a suitable ward), one did not respond to the request for a site visit to progress towards recruitment and, for one, regulatory approvals came after the other requisite number of POD sites had gained approval. Of the 16 recruited wards, nine were elderly care medicine and seven were surgical/trauma orthopaedic. Seven of the eight hospitals registered had one elderly care ward and one orthopaedic trauma ward. The remaining hospital site had two elderly care wards registered.

None of the wards/hospitals withdrew from the study.

Patient screening and recruitment rates

Screening and recruitment took place between August 2014 and February 2015. A total of 4449 patients admitted to the 16 wards were screened for eligibility, 3274 (73.6%) of whom were considered eligible. The most common reasons for exclusion at screening of the remaining 1175 patients were as follows: 538 (45.8%; 12.1% of those screened) had a recorded diagnosis of delirium on admission, 352 (30.0%; 7.9% of those screened) had an expected duration of stay of < 48 hours, 139 (11.8%; 3.1% of those screened) were not under the care of the ward medical team and 105 (8.9%; 2.4% of those screened) were receiving end-of-life care (Figure 4).

FIGURE 4.

The Consolidated Standards of Reporting Trials flow diagram. a, Withdrawals here are from researcher questionnaires; b, withdrawals here are from postal questionnaires; one patient in the POD arm withdrew from researcher visits at 30 days, but not from postal questionnaires at 3 months.

Delirium assessment was performed by the RAs on 1537 (34.5% of screened) of the 3274 eligible patients. The remaining 1737 (39.0% of screened) patients did not have a delirium assessment. The most common reasons for not performing a CAM assessment were as follows: research staff missed patient [691 (39.8% of those excluded)], ward staff advised not to approach [374 (21.5%)], patient unavailable [283 (16.3%)] and patient refused [246 (14.2%)].

Of the 1537 patients who were screened for delirium, 1418 (31.9% of screened) were assessed as not having prevalent delirium. The remaining 119 were excluded: 113 had prevalent delirium, and the reasons are unknown for six.

Of the 1418 patients assessed as not having delirium, 1340 (30.1% screened) either had capacity (n = 1182) or a consultee had been identified (n = 158); these were approached for participation. The remaining 78 patients were excluded as they were without capacity and a consultee had not been identified. Of the 1340 patients approached for participation, 626 were excluded. The most common reasons for exclusion were as follows: 459 (73.3% of those excluded) patients refused; 59 (9.4%) were discharged before consent was obtained; 29 (4.6%) were missed by the researcher; and, for 26 (4.2%), the consultee refused. Consent was obtained for 714 (16.0% of screened) patients, and 713 were registered to the study (one patient was discharged before registration): 343 were registered to the POD system of care and 370 were registered to control (see Figure 4). Figure 5 is the recruitment graph. Patient accruals to the study between the sites ranged from 65 to 105 (see Appendix 6, Table 50).

FIGURE 5.

Recruitment graph.

Eligibility violations

A total of 13 (1.8%) participants were identified as not fulfilling the eligibility criteria: five (1.5%) in the POD arm and eight (2.2%) in the control arm. The main criteria violated were as follows: the delirium assessment (CAM) was not performed (n = 1 in the POD arm and n = 6 in the control arm), and the participant had prevalent delirium on admission (n = 3 in POD and the POD arm and n = 2 in the control arm) (see Appendix 6, Table 51). Patients identified as breaching an eligibility criterion were included in all analyses.

Final follow-up

Thirty-three (4.6%) participants withdrew during the study period [15 (4.4%) from the POD arm and 18 (4.9%) from the control arm] (see Appendix 6, Table 52). Of these, 19 (57.6%) withdrew within 10 days of recruitment.

Characteristics of the screened and registered participants: generalisability

The characteristics of the screened and registered participants were similar with respect to age, sex and ethnicity (Table 9). In the screened and registered populations, the mean overall ages were 83.1 years [standard deviation (SD) 8.05 years] and 82.7 years (SD 7.84 years) respectively; female patients accounted, respectively, for 67.2% and 68.3% of the populations; and 89.3% and 91.7%, respectively, of the populations were of white ethnicity. Participant age and ethnicity were broadly similar across sites: the mean overall age varied between 79.0 years (SD 7.34 years) and 85.1 years (SD 7.58 years), and between 83.8% and 97.6% of participants were of white ethnicity (small differences due to more missing data for some sites). Some differences between sites were noted with respect to sex; female participants accounted for between 49.2% and 100.0% of participants (see Appendix 6, Table 53).

Baseline characteristics

The two arms were well balanced with respect to residence, hearing aid use, benzodiazepines use and comorbidities, although some imbalance between groups was evident for all other characteristics, namely reason for admission, ward type, cognitive impairment and/or dementia, highest NEWS category within 48 hours of admission, visual impairment, hearing impairment, and opiates and antihistamines prescribed (Table 10). Residence and hearing impairment were balanced across sites; however, some imbalance between sites was apparent for all other characteristics (see Appendix 6, Table 54).

Intervention fidelity

Ten health-care professionals with experience in older people’s care assessed fidelity. The mean score for each domain was as follows: installation, 4.5 points (range 3.5–5.0 points); delivery, 32.6 points (range 27.3–38.3 points); coverage, 7.9 points (range 4.2–10.1 points); and duration, 0.38 points (range 0–1.0 points). 73 Of the 10 delirium risk factors, infection, nutrition, hypoxia and pain were the most consistently addressed, and cognitive impairment, sensory impairment and multiple medications were the least consistently addressed. 73 Overall fidelity to the intervention was assessed as being high (≥ 80%) in two wards, medium (51–79%) in five wards and low (≤ 50%) in one ward.

Staff

Contamination data were received from all sites [two sites (sites 2 and 4) provided data by telephone or e-mail only]. Site 2 stated that staff were never moved to other wards from the trauma ward and no staff were brought onto the ward. No data were provided for the elderly care ward at this site. Site 4 stated that wards did not keep any records of staff movement.

During the 1-week data collection period, there were 216 reports of staff moving into the 12 study wards that were providing data: 115 on elderly care wards and 101 on orthopaedic trauma wards, most commonly health-care assistants (51.9%) (see Appendix 6, Table 56).

Only 13 staff moves off the ward were recorded during the 1-week data collection period: four from elderly care wards and nine from orthopaedic trauma wards (see Appendix 6, Table 56).

Delirium incidence rates

The incidence rates of new-onset delirium were similar between arms at the sites randomised at the hospital level and at those randomised at the ward level (see Appendix 6, Table 57). However, incidence rates were lower when ward-level randomisation was used.

Incidence rates of new-onset delirium were similar between arms for participants recruited during the first 3 months of sites opening to recruitment and for participants recruited between 3 and 6 months of sites opening to recruitment, although incidence rates were lower during the later 3 months of recruitment (see Appendix 6, Table 58).

Patients

During their hospital stays, 135 (18.9%) participants moved wards: 58 (16.9%) in the POD group and 77 (20.8%) in the control group (see Appendix 6, Table 59). Among the sites, the percentage of participants moving wards ranged from 10.0% to 25.8% (see Appendix 6, Table 60).

Wards

No ward reported any new multicomponent delirium prevention measures during the study period. Four POD wards introduced service improvements consisting of dementia training; observations using electronic handheld devices; attempts to decrease noise levels; and identification of patients at risk of delirium with education on hearing aids, nutrition and hydration. One control ward introduced a new rounding chart.

Confusion Assessment Method assessments

Taking into account the length of stay and excluding the assessments not expected as a result of death, withdrawal or discharge, of an expected 5645 CAM assessments, 5065 (89.7%) were completed during the first 10 days of recruitment (Table 12).

Non-completion rates in sites ranged from 3.5% to 14.8%. 59 The main reasons for non-completion of the CAM were participants were too ill [n = 186 (32.1%)] or participant refusal [n = 163 (28.1%)] (see Appendix 6, Table 61).

Of the 5065 CAM assessments, six (0.1%) had missing responses to CAM questions, two (0.04%) omitted the AMTS and 25 (0.5%) omitted the MotYB test (see Appendix 6, Table 62).

At 30 days, out of an expected 629 CAM assessments, 513 (81.6%) were completed (Table 13).

Non-completion rates of the 30-day CAM in sites ranged from 2.8% to 30.6% (see Appendix 6, Table 63). More 30-day CAM assessments were not performed for participants in the POD group (n = 78) than for those in the control group (n = 38). Similar reasons for non-completion of the CAM were evident across the groups, although some differences between groups were noted for participant refusal (POD arm, 29.5%; control arm, 15.8%) and participants moving out of the area (POD arm, 12.8%; control arm, 21.1%) (see Appendix 6, Table 64).

Questionnaire return rates

Return rates of the questionnaire booklets to the CTRU were as follows: at baseline, 699 (98.0% of 713 registered participants); at 30 days, 511 (81.8% of 625 expected); and, at 3 months, 400 (70.5% of 567 expected) (see Appendix 6, Table 65). Participant age, sex, ethnicity and residence were broadly similar between those who did and those who did not complete the 30-day researcher questionnaire (see Appendix 6, Table 66).

The most common reasons for non-completion of the 30-day and 3-month questionnaire booklets were as follows: could not contact participant [27 (23.7%) and 92 (55.1%) for the 30-day and 3-month questionnaire booklets, respectively] and participant refused to complete them [26 (22.8%) and 31 (18.6%) for the 30-day and 3-month questionnaire booklets, respectively] (see Appendix 6, Tables 67 and 68).

Questionnaire compliance

Of the 511 30-day follow-ups, 313 (61.3%) were undertaken within ± 2 days of the due date [mean 28.9 (SD 4.93) days]. Of the 400 3-month follow-ups, 259 (64.8%) were undertaken within ± 2 weeks of the due date [mean 102.4 (SD 19.39) days].

Primary outcome

Fifty-seven (8.0%) of the 713 participants developed new-onset delirium within 10 days of recruitment: 24 (7.0%) of the 343 participants registered to wards delivering the POD system of care and 33 (8.9%) of the 370 participants registered to the control wards. New-onset delirium was slightly higher in orthopaedic trauma wards than in elderly care wards (10.0% vs. 6.4%).

Multilevel logistic regression analysis (adjusting for participant characteristics collected at registration and for ward type) was used to explore the between-group differences in delirium incidence. Although there was evidence that participants in the POD arm had lower odds of developing delirium, this result was not statistically significant (odds ratio 0.68, 95% CI 0.37 to 1.26; p-value = 0.2225) (Table 14). An unadjusted analysis confirmed this finding (odds ratio 0.77, 95% CI 0.44 to 1.33).

Missing data

The return rate of the EQ-5D was 98.6%, 77.5% and 65.3% at baseline, 1 month and 3 months, respectively (94–98% fully completed) (see Appendix 5, Table 34). The completion rate of the resource use questionnaire was lower at 48.7%. Participants with cognitive impairment at baseline were less likely to return the questionnaire than individuals with no cognitive impairment (see Appendix 5, Table 35).

Baseline imbalance

There was some baseline imbalance between the groups, and adjustment was required. QALYs were adjusted using baseline EQ-5D, age, ward type (orthopaedic vs. general), sex and cognitive impairment status (yes vs. no).

Validity of patient outcome assessments

A significant, positive correlation existed between the EQ-5D and NEADL scale scores at 3 months (r = 0.66), indicating that they measure similar constructs in this patient group (see Appendix 5, Figure 18). The trial sample had lower EQ-5D scores at baseline than UK age-matched population norm averages (reported in Kind et al. 77) (see Appendix 5, Table 37). Patients who experienced delirium had a lower average baseline EQ-5D score than those who did not (0.09, compared with 0.26), and this difference was maintained across the different time points (1 month: 0.28, compared with 0.50; and 3 months: 0.15, compared with 0.43) (see Appendix 5, Table 38).

Validity of proxy outcomes assessments

At baseline, proxy-completed EQ-5D values were similar to self-completed (by participants) EQ-5D values, but, at 1 and 3 months, proxy-completed (or aided) EQ-5D completion underestimated quality of life (see Appendix 5, Table 39).

Costs

The POD group participants had higher average resource use for every health-care resource except general practitioner (GP) surgery visits and psychiatrist, psychologist or counsellor visits (see Appendix 5, Table 41). Participants in the POD group had, on average, 2.2 more overnight days in hospital and 1 more day in nursing/residential homes. Overall, the hospital inpatient stay appeared to be driving costs: mean costs were £4965 for the POD group and £4365 for the control group (see Appendix 5, Table 42). The average cost of the POD intervention was estimated as £10.98 per patient (see Appendix 5, Table 40).

Quality-adjusted life-years

The EQ-5D scores at baseline were slightly higher for the POD group than for the control group [mean 0.261 (SD 0.393) for the POD group vs. 0.234 (SD 0.347) for the control group]. Despite the fewer cases of delirium in the POD group, there were negligible between-group differences in QALYs, although, in all analyses, these were in favour of the control arm.

Cost-effectiveness

The trial-based ICER was dominated by standard care (see Appendix 5, Table 43). That is, the POD intervention resulted in higher costs and lower QALYs, albeit the QALY differential was negligible. The difference in cost varied from £920 in the complete-case group to £1127 for the complete-case and imputed items group. The difference in QALY varied from –0.01 in both imputation groups to –0.02 in the complete-case analysis (see Appendix 5, Table 43). NHS total cost and QALYs were replicated 10,000 times in a Monte Carlo simulation (see Appendix 5, Figures 20–22). Using a £20,000 per QALY threshold, the probability that the POD intervention was cost-effective was 0.01 (1% chance) in a simulation using adjusted QALYs and complete-case and imputed items. This chance increased to 10% when using unadjusted QALYs and complete-case data only. The findings were robust to sensitivity analyses.

The health economics model (see Model development) was updated using information from the trial. There were differences between some parameter values used in the original model and those observed in the trial: lower delirium incidence, lower delirium rate reduction and much lower utility values. As POD appeared to result in additional resource use (a difference of £419), a sensitivity analysis was run in which this was added to the POD cost; see Appendix 5, Table 47, for the updated model parameters and assumptions. The updated model showed that the POD system of care had an incremental cost and QALY of £1775 and 0.11, respectively, resulting in an ICER of £16,133, which indicated that the POD intervention was cost-effective (see Appendix 5, Table 48). The probabilistic sensitivity analyses yielded mean incremental costs and QALYs of £1774 and 0.11, respectively, and an ICER of £15,454. The cost-effectiveness acceptability curve with a ‘willingness to pay’ of £20,000 showed that POD had a 100% chance of being cost-effective (see Appendix 5, Figure 23). The results of the trial and model-based analyses were conflicted, and thus limit the confidence we can place on the economic evaluation results. It is unclear why this divergence occurred. Clearly, the model time horizon was much greater than that for the trial analysis and it is possible that the (albeit small) differential in delirium occurrence, when extrapolated over a lifetime, fully reflected the costs and benefits of the intervention, and thus explains to some degree the contrast between trial and model outcomes. The model also fixes the assumed relationship between delirium incidence and outcomes (length of stay, mortality and health-related quality of life), whereas, in the trial, we assessed the relationships directly; it could be that there was an unexpected or lower relationship between these factors than anticipated or that data quality led to bias.

There were significant issues relating to data quality (e.g. missing data and reliance on proxy reports); future research should seek to identify the optimal strategy for data collection in this population.

Delirium

Severity of delirium episodes, duration of delirium episodes and time to first episode of delirium (including persistent delirium) were similar between the two groups (see Appendix 6, Tables 69–74).

Falls

Nineteen falls were reported in wards receiving the POD system of care and 20 falls were reported in wards receiving control, with mean falls rates of 1.6 (SD 1.00) for the intervention group and 1.3 (SD 0.39) for the control group.

Length of hospital stay

The length of stay for patients who were discharged or who died while in hospital was similar between the groups: a mean of 9.7 days (SD 7.12 days) among those patients registered to POD and a mean of 9.8 days (SD 6.91 days) among those patients registered to the control.

Deaths

A total of 104 patient deaths were reported within 3 months of recruitment (14.6% of all registered patients): 56 (16.3% of patients registered) in the POD group and 48 (13.0% of patients registered) in the control group. Of these, 28 (26.9%) deaths occurred within 10 days of patient recruitment (see Appendix 6, Table 75). The number of deaths between the sites ranged from 5 (7.7%) to 22 (21.2%).

Discharge destination

Of those patients discharged, a larger proportion of patients registered to the POD group [176/248 (71.0%)] than patients registered to the control group [194/288 (67.4%)] were discharged home (Table 17).

Of the 536 patients discharged, 118 (22.0%) had a change in discharge destination from independent to institutionalised accommodation: 47 out of 248 (19.0%) in the intervention arm and 71 out of 288 (24.7%) in the control arm (Table 18).

Patient-reported outcomes

Raw (unadjusted) scores for the NEADL scale, Clinical Anxiety Scale and the Geriatric Depression Scale score showed little between-group differences, although control scores appeared very slightly higher for the NEADL at both baseline and 3 months (see Appendix 6, Tables 76–79).

Poor outcome

Poor outcome (defined as death, persistent delirium or change in accommodation at hospital discharge from home to residential care/nursing home or from residential home to nursing home) was similar: 80 out of 343 (23.3%) in the POD group and 72 out of 370 (19.5%) in the control group (see Appendix 6, Table 80).

Safety

There were no unexpected serious adverse events reported that were clearly attributable to the POD intervention.