Background
In developing interventions to improve clinical practice, it is advocated that researchers should adopt a systematic approach and provide explicit reporting of the intervention development process [
1]. The UK Medical Research Council’s (MRC) complex intervention framework recommends that intervention development be guided by best available evidence and appropriate theory [
2]. Systematic literature reviews can help in identifying, appraising and pooling available evidence. This can aid the selection of intervention components, as well as outcome measures to include as part of the overall evaluation. The use of appropriate theory can help in overcoming inherent limitations where intervention development involves a pragmatic approach based on researchers’ own implicit, and potentially biased, assumptions as to what is likely to be effective [
3,
4]. For example, theories can be used to generate testable hypotheses and explore potential causal mechanisms underlying the intervention’s effect. Although established systematic review methodologies exist which have been extensively detailed in the literature, the methods involved in identifying and/or developing appropriate theory are much less clear [
5]. A recognised limitation of the MRC framework is that it does not provide guidance on how theory can be incorporated into the intervention development process [
6].
Interventions aimed at improving clinical practice often require behaviour change among healthcare professionals (HCPs). For example, a number of studies have focussed on the implementation of different evidence-based guidelines by HCPs as the target behaviour [
7‐
9]. By incorporating behaviour change theory into intervention development, researchers can target causal determinants of behaviour/behaviour change, thus making interventions more likely to be effective [
10]. This requires a clear understanding of the target behaviour, as well as knowledge of relevant behaviour change theories, so that specific techniques can then be used as part of the intervention to elicit the required changes. A key challenge faced by researchers from non-health psychology backgrounds involves selecting a theory, or combination of theories, from the vast range of existing psychological theories and using these theories appropriately to understand and change target behaviours.
The development of the Theoretical Domains Framework (TDF) of behaviour change [
11] has gone some way to help overcome this challenge. The TDF simplifies psychological theory relevant to behaviour change, in order to make behavioural theories more accessible to researchers from non-health psychology backgrounds [
11]. TDF version 1 consists of 12 theoretical domains that are relevant to changing HCPs’ behaviour: ‘Knowledge’; ‘Skills’; ‘Social/professional role and identity’; ‘Beliefs about capabilities’; ‘Beliefs about consequences’; ‘Motivation and goals’; ‘Memory, attention and decision processes’; ‘Environmental context and resources’; ’Social influences’; ‘Emotion’; ‘Behavioural regulation’; ‘Nature of the behaviours’ [
11]. Eleven of the twelve theoretical domains are proposed to be mediators of behaviour change with ‘Nature of the Behaviours’ being the exceptional domain which relates to the key characteristics of the behaviour of interest as opposed to potential mediating mechanisms or influences [
11,
12]. The TDF has since been refined and version 2 consists of 14 theoretical domains [
13]. However, TDF version 1 (12 domains) is still in use [
7,
14,
15]. The TDF has been used as part of a systematic approach to intervention development in order to identify key theoretical domains that are perceived to influence HCPs’ behaviours [
1]. It provides a theoretically-robust evidence base to inform intervention design whereby domains are mapped to behaviour change techniques (BCTs) which form the intervention’s so-called ‘active ingredients’ [
10,
16]. This can help researchers to incorporate a theory-base into the intervention development phase.
The aim of the current study which formed part of a multiphase research project was to develop an intervention to improve appropriate polypharmacy in older people in primary care, drawing on relevant methodological advances in intervention development research, as outlined above. The use of multiple medicines, also termed polypharmacy, is increasingly common in older people [
17,
18] and ensuring ‘appropriate polypharmacy’ in this patient cohort, whereby prescribing is evidence-based and reflects patients’ clinical needs, is a challenge faced by practitioners that is of considerable clinical and economic importance, particularly in light of continuing growth in the size of the older population [
19]. Polypharmacy has been identified as the principal determinant of potentially inappropriate prescribing (PIP) in older populations [
4,
5] and linked to negative clinical consequences, including medication non-adherence, drug-interactions and adverse drug events (ADEs) [
6]. PIP in older people also places a considerable financial burden on health services [
4,
5]. The challenge of improving appropriate polypharmacy is further compounded by a lack of available evidence and guidelines to inform clinical practice when prescribing for older people who often suffer from more than one chronic condition (
i.e. multimorbidity) [
20].
The approach to intervention development that underpinned this research project aligns with the MRC framework by drawing on evidence and theory. The evidence base is drawn from the findings of an updated Cochrane review of interventions to improve appropriate polypharmacy in older people [
21] which identified a limited range of intervention types. These interventions were most commonly pharmaceutical care-based and typically involved HCPs conducting medication reviews. However, the quality of the available evidence was considered low, owing to risks of bias in the included studies, and details of intervention development and delivery were lacking in published reports [
21]. Accordingly, a more systematic approach, incorporating both evidence and theory, was recommended for the development of future interventions [
21]. The theory base for the current project was drawn from qualitative TDF-based interviews of general practitioners (GPs) and community pharmacists which we have reported elsewhere [
22]. During the qualitative interview phase, key theoretical domains were identified and mapped to BCTs that could be used as the basis of a theory- and evidence-based intervention. The current paper builds on this earlier work and outlines the systematic process that we used to develop an intervention using previously selected BCTs.
Discussion
This paper describes the systematic development of an intervention to improve appropriate polypharmacy in older people in primary care and serves to address the lack of theory-based and adequately described interventions in the related literature [
21]. The detailed analysis of the target behaviours (i.e. prescribing and dispensing of appropriate polypharmacy) that was undertaken using the TDF [
11] as the underpinning theoretical framework enabled us to identify key mediators (
i.e. barriers, facilitators) of behaviour change to target as part of the intervention [
22]. It has been proposed that by targeting specific behaviour change mediators, researchers will enhance the likely effectiveness of interventions [
10]. Hence, the intervention was specifically developed to target identified mediators of behaviour change using behaviour change techniques (BCTs) from an established taxonomy [
30]. The selection of BCTs was guided by previous methodological work by experts in the field whereby BCTs have been mapped to relevant theoretical domains from the TDF [
10,
16] (see Cadogan
et al. [
22] for full details).
In comparison to the initial baseline work (
i.e. TDF-based analysis of target behaviours, mapping of key theoretical domains to BCTs) for which we were able to draw on established methods and guidance [
22], the development of draft interventions using selected BCTs proved to be a challenging process for several reasons. Although the current BCT Taxonomy (version 1) [
30] provides definitions of each BCT and illustrative examples of how they can be operationalised, there is no single best approach to decide on how to draft interventions based on a given number of BCTs. A previous review of the TDF-based literature showed that few published studies have progressed through the entire process of TDF-based intervention development [
12]. Within the existing literature, the methods used by individual research groups to develop TDF-based interventions following mapping of BCTs to key theoretical domains have varied. For example, French
et al. [
1] reported that, following the mapping process, intervention development was based on a combination of the research team’s experience and feedback from colleagues, while Kolehmainen and Francis [
26] reported that an advisory team was established to help inform the process. Hence, it would appear that there is no consensus as to what is the most appropriate procedure for determining how best to operationalise and deliver selected BCTs as part of an intervention.
Ideally, these decisions should be guided by contextual information gathered from key stakeholders (
i.e. those delivering/receiving intervention) and informed by available evidence. The qualitative HCP interviews helped to provide the former, but despite having updated a Cochrane review [
21] as part of the overall project, the findings were of limited value in informing our decision process. Few of the interventions that were included in the review had been conducted specifically in primary care settings and specific intervention components had not been characterised using standardised terminology, such as BCTs. Hence, there was a lack of available evidence on which to base decisions as to how to operationalise and deliver BCTs.
The BCT Taxonomy [
30] has been used to retrospectively code interventions identified through systematic reviews [
31], in addition to developing behaviour change interventions. Although this will ultimately help to develop an evidence base to inform decisions regarding BCT operationalisation and delivery, this work is still at an early stage. The full potential of characterising behaviour change intervention components in terms of BCTs will not be realised until problems with the reporting of complex interventions are addressed, such as the lack of detailed description of intervention development and delivery that was identified in the Cochrane review [
21]. Recent guidance on the reporting of complex interventions [e.g. TIDieR (Template for intervention description and replication) [
32], WIDER (Workgroup for Intervention Development and Evaluation Research) [
33]] may go some way to help overcome these issues. In the interim, decisions as to how selected BCTs should be operationalised and delivered will rely on the judgement of individual research teams. This process should be based on the team members’ research experience and knowledge of relevant literature while following existing guidance [
1] and considering the local context, as well as what is likely to be feasible and acceptable to the target group.
The video demonstration component of the intervention aligned with a ‘work smarter, not harder’ approach that sought to limit any additional workload for GPs in prescribing appropriate polypharmacy [
34]. Thus, rather than introducing new behaviours or tasks for GPs to perform, we sought to enable GPs to use available time more efficiently by demonstrating how appropriate polypharmacy can be prescribed during routine consultations with older patients (‘Modelling or demonstrating of behaviour’) and emphasising the potentially positive consequences of performing this behaviour (‘Salience of consequences’). It was envisaged that the video would last the duration of an average GP consultation (i.e. ten minutes) in order to ensure that it was considered clinically authentic by the intervention targets (i.e. GPs). The online mode of delivery was chosen so that GPs could access the video at a time that would be convenient for them. The additional intervention components (
i.e. action plans, prompts/cues) sought to complement the video demonstration by enabling GPs to overcome the time barriers posed by the existing work environment to performing the target behaviour through the use of action plans and prompts/cues (Table
1). It has been proposed that a ‘work smarter, not harder’ type of approach could enhance the likelihood of achieving improvements in patient care [
34].
It must be noted that achieving appropriate polypharmacy in older people is a highly complex clinical challenge and is not limited to changing GPs’ prescribing behaviour alone. A range of other issues need to be addressed in order to optimise medication use in older people, including the lack of available evidence and guidelines to inform clinical practice when prescribing for older multimorbid patients [
20] and patient-level barriers when attempting to implement prescribing changes (e.g. disagreement with the appropriateness of prescribing changes) [
35]. In light of this complexity, it is unlikely that a single intervention could ever address all of the encompassing issues and challenges. Therefore, a combination of interventions will likely be required. The intention of the intervention developed in the current study was to introduce small, but potentially sustainable, changes in GPs’ current clinical practice aimed at improving prescribing for older people. This is in accordance with available guidance on the development of behaviour change interventions which recommends that change should be introduced incrementally and proposes that building on small successes over time can be more effective than trying to do too much too quickly [
6]. If the current intervention proves effective in a future trial evaluation, it could be combined with other interventions to form part of a large multi-strand approach to optimise medication use in older people.
The feasibility screening process was an important methodological step in the development of our intervention as there were several ways in which the combination of BCTs could have been operationalised. The APEASE criteria [
6] helped us to consider key factors such as the likely acceptability and practicability of each draft intervention before undertaking any formal feasibility study. For example, due to the anticipated difficulties in the co-ordination of care between general practices and community pharmacies and the negative impact that this would have on the practicability of a community pharmacy-based intervention, the GP-targeted intervention was selected as the most viable option for further evaluation. Applying these criteria also helped us to identify that one of the draft interventions (i.e. the patient-targeted intervention) did not target the pre-specified behaviours that we had set out to change (i.e. prescribing and dispensing of appropriate polypharmacy). A future feasibility study will help us to determine if further refinements to the intervention are required before progressing to a larger scale evaluation in a randomised study.
Strengths and limitations
The main strength of this study was that it sought to overcome limitations with previously evaluated interventions to improve appropriate polypharmacy in older people [
21] by adopting a systematic approach using both evidence and an underlying theory-base as advocated by the MRC framework [
2]. Interventions aimed at improving healthcare practice have often not included an underlying theory base [
36,
37]. This prevents researchers and clinicians from understanding the mechanisms of change underlying the interventions’ effects. In addition, problems have been noted with the reporting of behaviour change interventions in the literature, such as a lack of detailed descriptions of interventions and the use of inconsistent terminology to characterise intervention content [
38]. This makes it difficult to replicate interventions and to either compare the effects of different interventions or to pool data for specific intervention components across studies. The selection of BCTs from an established taxonomy in the current intervention will ensure that the intervention content is described in detail using standardised terminology and this will ultimately help to overcome the above noted limitations of previous research.
As a limitation of our approach, it must be noted that the intervention development work was underpinned by TDF-based qualitative interviews of healthcare professionals which limits the generalisability of the findings [
22]. However, participants were sampled across the five administrative health areas in Northern Ireland, and this geographical spread enhanced the transferability of the findings. Given the similarities in general practice across the UK, it is likely that many of the identified barriers and facilitators under each of the theoretical domains would be applicable to GPs across the UK. This claim is supported by the findings of a previous study that compared qualitative TDF-based interview findings of healthcare professionals from different countries, and identified considerable overlap in terms of identified barriers and facilitators under a number of theoretical domains [
39].
It must also be noted that there is a degree of subjectivity with the employed intervention development process as selected BCTs could have been operationalised in a number of different ways [
1]. Hence, it is uncertain whether another research team would have operationalised selected BCTs in similar ways and produced exact replicates of the interventions that were developed [
26]. We attempted to overcome this by drafting a range of interventions through which selected BCTs could be operationalised and selecting an intervention for further testing through the feasibility screening process that was guided by the APEASE criteria [
6].
Finally, as the BCT Taxonomy [
30] is a relatively new methodological tool, further evidence is required to ensure that particular BCTs achieve behaviour change through the proposed theoretical domains to which they have been mapped by experts in the field [
16]. In addition, while our selected BCTs targeted multiple theoretical domains (
e.g. Modelling or demonstrating the behaviour targeted ‘Skills’, ‘Beliefs about capabilities and ‘Social influences’), it is not yet clear whether targeting an increased number of domains results in more effective interventions [
40]. However, by adopting a systematic and theory-based approach to intervention development using the TDF and specifying the intervention’s content in terms of BCTs, we can now make explicit assumptions about the hypothesised mechanisms of change underlying the intervention’s effect [
1]. Thus, we can now hypothesise that our GP-targeted intervention that comprises four BCTs will effect change in GPs’ prescribing behaviour to improve appropriate polypharmacy by targeting mediators of behaviour change across eight theoretical domains. As further progress is made in conducting trial evaluations of TDF-based behaviour change interventions, an evidence base will begin to emerge that will help to inform the selection of BCTs to target specific theoretical domains.
Acknowledgements
The authors would like to thank all of the healthcare professionals who agreed to take part in the qualitative interviews. The authors would also like to thank Ms. Johanne Barry (Queen's University Belfast), Dr. Nigel Hart (Queen's University Belfast) and Dr. June Tordoff (University of Otago, New Zealand) for their feedback on the interview topic guides. The authors are especially grateful to Mrs. Claire Leathem and colleagues in the Northern Ireland Clinical Research Network for their assistance with participant recruitment.