Complex Interventions In Primary Care Research Articles

Design of the Initial Medication Adherence (IMA) complex intervention in Primary Care: "NonInitiators - Modelling study”

The International Journal of Integrated Care (IJIC) is an online, open-access, peer-reviewed scientific journal that publishes original articles in the field of integrated care on a continuous basis.IJIC has an Impact Factor of 5.120 (2020 JCR, received in June 2021)

The CRIAA Program complex intervention in primary care to support women and their families in breastfeeding: Study protocol for a pilot trial.

To report a pilot study protocol to assess the feasibility of a complex intervention, in the primary healthcare context, to support women and their families in breastfeeding. A pilot/feasibility trial with control and intervention groups. The study will be conducted in two primary healthcare centres with 40 childbearing women (20 control group; 20 intervention group), with their partner/meaningful person and their respective healthcare professionals. Intervention group participants will receive the intervention: (a) in a breastfeeding workshop during their third trimester of pregnancy; and (b) via virtual breastfeeding support for six months postpartum. Health professionals will be trained to deliver the intervention. The control group will receive standard care in the outpatient clinic. The pilot will help determine the intervention's feasibility. Data collected pre-intervention, 10-days postpartum and two-, four-, and six-months postpartum will provide estimates of the intervention's preliminary effects on self-efficacy and main outcomes. Research Ethics Committee approval was obtained in April 2019. Breastfeeding support is a complex reality influenced by multiple factors. Therefore, approaches to breastfeeding are also, requiring interventions that address its multidimensional nature, including all actors involved. The proposed intervention will be applied by an interdisciplinary professional health team, allowing for its incorporation into standard practice and its perpetual maintenance. The study will produce an original, comprehensive, complex intervention addressing contextual, and organizational factors to promote breastfeeding support using an interdisciplinary and family-based approach; breastfeeding self-efficacy is the core concept. The program evaluation and feasibility study will permit exploration of the integration of the intervention's novel aspects into the daily work of professionals and reveal how to better use existing resources in a full-scale clinical trial. ClinicalTrials.gov ID: NCT03944642.

Cost effectiveness of an intervention to increase uptake of hepatitis C virus testing and treatment (HepCATT): cluster randomised controlled trial in primary care

ObjectiveTo evaluate the effectiveness and cost effectiveness of a complex intervention in primary care that aims to increase uptake of hepatitis C virus (HCV) case finding and treatment.DesignPragmatic, two armed,...

Increasing uptake of hepatitis C virus infection case-finding, testing, and treatment in primary care: evaluation of the HepCATT (Hepatitis C Assessment Through to Treatment) trial

BackgroundHepatitis C virus (HCV) infection is a key cause of liver disease but can be cured in more than 95% of patients. Around 70 000 people in England may have undiagnosed HCV infection and many more will not have been treated. Interventions to increase case-finding in primary care are likely to be cost-effective; however, evidence of effective interventions is lacking. The Hepatitis C Assessment Through to Treatment (HepCATT) trial assessed whether a complex intervention in primary care could increase case-finding, testing, and treatment of HCV.AimTo investigate the feasibility and acceptability of the HepCATT intervention.Design and settingA qualitative study with primary care practice staff from practices in the south west of England taking part in the HepCATT trial.MethodSemi-structured interviews were carried out with GPs, nurses, and practice staff to ascertain their views of the HepCATT intervention at least 1 month after implementing the intervention in their practice. Normalisation process theory, which outlines the social processes involved in intervention implementation, informed thematic data analysis.ResultsParticipants appreciated the HepCATT intervention for increasing knowledge and awareness of HCV. Although some initial technical difficulties were reported, participants saw the benefits of using the audit tool to systematically identify patients with HCV infection risk factors and found it straightforward to use. Participants valued the opportunity to discuss HCV testing with patients, especially those who may not have been previously aware of HCV risk. Future implementation should consider fully integrating software systems and additional resources to screen patient lists and conduct tests.ConclusionWhen supported by a complex intervention, primary care can play a crucial role in identifying and caring for patients with HCV infection, to help stem the HCV epidemic, and prevent HCV-related illness.

Understanding Implementation of Complex Interventions in Primary Care Teams.

The implementation of interventions to support practice change in primary care settings is complex. Pragmatic strategies, grounded in empiric data, are needed to navigate real-world challenges and unanticipated interactions with context that can impact implementation and outcomes. This article uses the example of the "5As Team" randomized control trial to explore implementation strategies to promote knowledge transfer, capacity building, and practice integration, and their interaction within the context of an interdisciplinary primary care team. We performed a qualitative evaluation of the implementation process of the 5As Team intervention study, a randomized control trial of a complex intervention in primary care. We conducted thematic analysis of field notes of intervention sessions, log books of the practice facilitation team members, and semistructured interviews with 29 interdisciplinary clinician participants. We used and further developed the Interactive Systems Framework for dissemination and implementation to interpret and structure findings. Three themes emerged that illuminate interactions between implementation processes, context, and outcomes: (1) facilitating team communication supported collective and individual sense-making and adoption of the innovation, (2) iterative evaluation of the implementation process and real-time feedback-driven adaptions of the intervention proved crucial for sustainable, context-appropriate intervention impact, (3) stakeholder engagement led to both knowledge exchange that contributes to local problem solving and to shaping a clinical context that is supportive to practice change. Our findings contribute pragmatic strategies that can help practitioners and researchers to navigate interactions between context, intervention, and implementation factors to increase implementation success. We further developed an implementation framework that includes sustained engagement with stakeholders, facilitation of team sense-making, and dynamic evaluation and intervention design as integral parts of complex intervention implementation. NCT01967797. 18 October 2013.

Development of an intervention to reduce antibiotic use for childhood coughs in UK primary care using critical synthesis of multi-method research

BackgroundOveruse of antibiotics contributes to the global threat of antimicrobial resistance. Antibiotic stewardship interventions address this threat by reducing the use of antibiotics in occasions or doses unlikely to be effective. We aimed to develop an evidence-based, theory-informed, intervention to reduce antibiotic prescriptions in primary care for childhood respiratory tract infections (RTI). This paper describes our methods for doing so.MethodsGreen and Krueter’s Precede/Proceed logic model was used as a framework to integrate findings from a programme of research including 5 systematic reviews, 3 qualitative studies, and 1 cohort study. The model was populated using a strength of evidence approach, and developed with input from stakeholders including clinicians and parents.ResultsThe synthesis produced a series of evidence-based statements summarizing the quantitative and qualitative evidence for intervention elements most likely to result in changes in clinician behaviour. Current evidence suggests that interventions which reduce clinical uncertainty, reduce clinician/parent miscommunication, elicit parent concerns, make clear delayed or no-antibiotic recommendations, and provide clinicians with alternate treatment actions have the best chance of success. We designed a web-based within-consultation intervention to reduce clinician uncertainty and pressure to prescribe, designed to be used when children with RTI present to a prescribing clinician in primary care.ConclusionsWe provide a worked example of methods for the development of future complex interventions in primary care, where multiple factors act on multiple actors within a complex system. Our synthesis provided intervention guidance, recommendations for practice, and highlighted evidence gaps, but questions remain about how best to implement these recommendations. The funding structure which enabled a single team of researchers to work on a multi-method programme of related studies (NIHR Programme Grant scheme) was key in our success.Trial registrationThe feasibility study accompanying this intervention was prospectively registered with the ISRCTN registry (ISRCTN23547970), on 27 June 2014.

Achieving change in primary care--causes of the evidence to practice gap: systematic reviews of reviews.

BackgroundThis study is to identify, summarise and synthesise literature on the causes of the evidence to practice gap for complex interventions in primary care.DesignThis study is a systematic review of reviews.MethodsMEDLINE, EMBASE, CINAHL, Cochrane Library and PsychINFO were searched, from inception to December 2013. Eligible reviews addressed causes of the evidence to practice gap in primary care in developed countries. Data from included reviews were extracted and synthesised using guidelines for meta-synthesis.ResultsSeventy reviews fulfilled the inclusion criteria and encompassed a wide range of topics, e.g. guideline implementation, integration of new roles, technology implementation, public health and preventative medicine. None of the included papers used the term “cause” or stated an intention to investigate causes at all. A descriptive approach was often used, and the included papers expressed “causes” in terms of “barriers and facilitators” to implementation. We developed a four-level framework covering external context, organisation, professionals and intervention. External contextual factors included policies, incentivisation structures, dominant paradigms, stakeholders’ buy-in, infrastructure and advances in technology. Organisation-related factors included culture, available resources, integration with existing processes, relationships, skill mix and staff involvement. At the level of individual professionals, professional role, underlying philosophy of care and competencies were important. Characteristics of the intervention that impacted on implementation included evidence of benefit, ease of use and adaptability to local circumstances. We postulate that the “fit” between the intervention and the context is critical in determining the success of implementation.ConclusionsThis comprehensive review of reviews summarises current knowledge on the barriers and facilitators to implementation of diverse complex interventions in primary care. To maximise the uptake of complex interventions in primary care, health care professionals and commissioning organisations should consider the range of contextual factors, remaining aware of the dynamic nature of context. Future studies should place an emphasis on describing context and articulating the relationships between the factors identified here.Systematic review registrationPROSPERO CRD42014009410 Electronic supplementary materialThe online version of this article (doi:10.1186/s13012-016-0396-4) contains supplementary material, which is available to authorized users.

Six-year follow-up of the SPHERE RCT: secondary prevention of heart disease in general practice

ObjectiveTo determine the long-term effectiveness of a complex intervention in primary care aimed at improving outcomes for patients with coronary heart disease.DesignA 6-year follow-up of a cluster randomised controlled trial,...

Effectiveness of multicomponent interventions in primary healthcare settings to promote continuous smoking cessation in adults: a systematic review

ObjectiveThe objective of the present review is to evaluate multicomponent/complex primary care (PC) interventions for their effectiveness in continuous smoking abstinence by adult smokers.DesignA systematic review of randomised and non-randomised...

Effectiveness of strategies to facilitate uptake or implementation of complex interventions: A systematic review of reviews

Introduction Research has consistently shown that many effective complex interventions are not taken up in practice. Getting evidence or complex interventions implemented into routine practice is often a challenge, particularly in primary care. Complex interventions are defined as interventions with several interacting components, e.g. prescribing decision support to aid guideline implementation, web-based self-management programme for people with type 2 diabetes. To bridge this evidence-to-practice gap, it is important to use effective methods/strategies to optimize implementation. Aim/objectives Assess the effectiveness of different strategies (single or multifaceted) for optimizing implementation of complex interventions; Assess the effects of strategies in different clinical areas (e.g. prevention, guideline, prescribing); Identify active components that contribute towards effective implementation; Describe cost-effectiveness evidence of these strategies. Method Five electronic databases were searched until December 2013. Citations and full-text papers were independently screened by two reviewers against pre-defined selection criteria [population: primary care in developed countries; intervention: implementation of complex interventions, by using single/multifaceted implementation strategies; comparison(s): usual care, no strategy, another strategy (single/multifaceted); outcomes: degree of implementation, e.g. process, professionals' behaviour or performance; study design: reviews]. Data were extracted using standardized data abstraction forms. A multi-step systematic process was developed; results were described narratively and the synthesis was guided by the pre-defined research questions. Findings 91 reviews were included. For dichotomous outcomes, effects of educational outreach visits, audit & feedback, educational meetings and computerized reminders were small-moderate (some more variable than others). Multifaceted strategies were not necessarily better than single strategies. However, multifaceted strategies including organizational interventions (redefined role, enhanced multidisciplinary team work) appeared to be more effective in changing practice. Active (and inactive) components that contributed towards the effectiveness of implementation were identified. There was limited evidence on the cost-effectiveness of using these implementation strategies. How the research advances dissemination and implementation research This work will provide a comprehensive overview of the topic by providing a deeper understanding of how to implement evidence-based approaches to improve service delivery and quality of patient care; and inspire individuals to think differently when planning and implementing a complex intervention in primary care. Implications for practice and future research were drawn from the findings of this review. Funding This Project (SPCR FR4 project number: 122) is funded by the National Institute of Health Research (NIHR) School for Primary Care Research (SPCR). This paper presents independent research funded by the National Institute of Health Research (NIHR). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

Adolescent seasonal allergic rhinitis and the impact of health-care professional training: cluster randomised controlled trial of a complex intervention in primary care.

Background:Seasonal allergic rhinitis is typically poorly managed, particularly in adolescents, in whom it is responsible for considerable morbidity. Our previous work has demonstrated that if poorly controlled this can impair educational performance.Aim:The primary aim of this trial was to assess the impact of a primary care–based professional training intervention on clinical outcomes in adolescents with seasonal allergic rhinitis. Methods:Cluster trial in which UK general practice staff were randomised to a short, intensive workshop on the evidence-based management of seasonal allergic rhinitis. The primary outcome measure was the change in the validated Rhinoconjunctivitis Quality of Life Questionnaire with Standardized Activities (RQLQ(S)) score between baseline and 6 weeks post intervention (minimal clinically important difference=0.5). Secondary outcome measures of interest included health-care professionals’ knowledge and confidence in managing seasonal allergic rhinitis, number of seasonal allergic rhinitis-related consultations, relevant treatments prescribed and symptom scores.Results:Thirty-eight general practices were randomised (20 in the intervention arm) and 246 patients (50.2% males, mean age 15 years) were included in the primary outcome analysis. Health-care professionals’ knowledge and confidence of the clinical management of seasonal allergic rhinitis improved. This did not, however, result in clinically or statistically significant improvements in RQLQ(S): −0.15, (95% confidence interval, −0.5 to +0.2). There were no differences in consultation frequency, treatments issued for seasonal allergic rhinitis or symptom scores.Conclusions:Although associated with increases in professionals’ self-assessed confidence and understanding of seasonal allergic rhinitis management, this intensive training workshop did not translate into improvements in adolescents’ disease-specific quality of life or a reduction in rhinitis symptoms.

Addressing the evidence to practice gap for complex interventions in primary care: a systematic review of reviews protocol

IntroductionGetting the results of research implemented into routine healthcare is often a challenge. The disconnect between the development and implementation of evidence into practice is called the ‘second translational gap’...

Psychosocial Interventions for Alcohol Use Among Problem Drug Users: Protocol for a Feasibility Study in Primary Care

BackgroundAlcohol use is an important issue among problem drug users. Although screening and brief intervention (SBI) are effective in reducing problem alcohol use in primary care, no research has examined this issue among problem drug users.ObjectiveThe objective of this study is to determine if a complex intervention including SBI for problem alcohol use among problem drug users is feasible and acceptable in practice. This study also aims to evaluate the effectiveness of the intervention in reducing the proportion of patients with problem alcohol use.MethodsPsychosocial intervention for alcohol use among problem drug users (PINTA) is a pilot feasibility study of a complex intervention comprising SBI for problem alcohol use among problem drug users with cluster randomization at the level of general practice, integrated qualitative process evaluation, and involving general practices in two socioeconomically deprived regions. Practices (N=16) will be eligible to participate if they are registered to prescribe methadone and/or at least 10 patients of the practice are currently receiving addiction treatment. Patient must meet the following inclusion criteria to participate in this study: 18 years of age or older, receiving addiction treatment/care (eg, methadone), or known to be a problem drug user. This study is based on a complex intervention supporting SBI for problem alcohol use among problem drug users (experimental group) compared to an “assessment-only” control group. Control practices will be provided with a delayed intervention after follow-up. Primary outcomes of the study are feasibility and acceptability of the intervention to patients and practitioners. Secondary outcome includes the effectiveness of the intervention on care process (documented rates of SBI) and outcome (proportion of patients with problem alcohol use at the follow-up). A stratified random sampling method will be used to select general practices based on the level of training for providing addiction-related care and geographical area. In this study, general practitioners and practice staff, researchers, and trainers will not be blinded to treatment, but patients and remote randomizers will be unaware of the treatment.ResultsThis study is ongoing and a protocol system is being developed for the study. This study may inform future research among the high-risk population of problem drug users by providing initial indications as to whether psychosocial interventions for problem alcohol use are feasible, acceptable, and also effective among problem drug users attending primary care.ConclusionsThis is the first study to examine the feasibility and acceptability of complex intervention in primary care to enhance alcohol SBI among problem drug users. Results of this study will inform future research among this high-risk population and guide policy and service development locally and internationally.

Does GP training in depression care affect patient outcome? - A systematic review and meta-analysis

BackgroundPrimary care practices provide a gate-keeping function in many health care systems. Since depressive disorders are highly prevalent in primary care settings, reliable detection and diagnoses are a first step to enhance depression care for patients. Provider training is a self-evident approach to enhance detection, diagnoses and treatment options and might even lead to improved patient outcomes.MethodsA systematic literature search was conducted reviewing research studies providing training of general practitioners, published from 1999 until May 2011, available on the electronic databases Medline, Web of Science, PsycINFO and the Cochrane Library as well as national guidelines and health technology assessments (HTA).Results108 articles were fully assessed and 11 articles met the inclusion criteria and were included. Training of providers alone (even in a specific interventional method) did not result in improved patient outcomes. The additional implementation of guidelines and the use of more complex interventions in primary care yield a significant reduction in depressive symptomatology. The number of studies examining sole provider training is limited, and studies include different patient samples (new on-set cases vs. chronically depressed patients), which reduce comparability.ConclusionsThis is the first overview of randomized controlled trials introducing GP training for depression care. Provider training by itself does not seem to improve depression care; however, if combined with additional guidelines implementation, results are promising for new-onset depression patient samples. Additional organizational structure changes in form of collaborative care models are more likely to show effects on depression care.

Methodological issues in pragmatic trials of complex interventions in primary care

A distinction in trial design is made between explanatory (or efficacy) and pragmatic (or effectiveness) trials.1 These terms, originally coined by Schwartz and Lellouch in 1967, are used to describe trials that either test causal research hypotheses to determine whether an intervention works in tightly controlled conditions to achieve optimal efficacy and/or to understand the key mechanism of action (explanatory); or that help choose between options for care under the usual conditions in which those options may be offered (pragmatic). The pragmatic–explanatory distinction really comprises a continuous spectrum1 with many elements, from the breadth of eligibility criteria, the flexibility in intervention delivery, expertise of those delivering treatment, degree of standardisation of intervention protocol, the efforts to ensure compliance, through to specific approaches to analysis. Pragmatic trials are increasingly adopted to test the effectiveness of complex interventions for patients in primary care, but may have explanatory elements. The Medical Research Council Framework for the development and evaluation of complex interventions provides helpful guidance, as complex interventions involve a number of separate but interacting components which are likely to be important to the success of the intervention, although the ‘active ingredients’ are often difficult to specify.2,3 In developing a novel, complex intervention comprising separate elements — for example, an education package with exercises for back pain — a rigorous …

Lifting the lid of the "black intervention box" - the systematic development of an action competence programme for people with screen-detected dysglycaemia

BackgroundThe evidence gained from effective self-management interventions is often criticised for the ambiguity of its active components, and consequently the obstruction of their implementation into daily practice.Our aim is to report how an intervention development model aids the careful selection of active components in an intervention for people with dysglycaemia.MethodsThe first three phases of the UK Medical Research Council's model for developing complex interventions in primary care were used to develop a self-management intervention targeting people with screen-detected dysglycaemia. In the preclinical phase, the expected needs of the target group were assessed by review of empirical literature and theories. In phase I, a preliminary intervention was modelled and in phase II, the preliminary intervention was pilot tested.ResultsIn the preclinical phase the achievement of health-related action competence was defined as the overall intervention goal and four learning objectives were identified: motivation, informed decision-making, action experience and social involvement. In Phase I, the educational activities were defined and the pedagogical tools tested. In phase II, the intervention was tested in two different primary healthcare settings and adjusted accordingly. The 18-hour intervention "Ready to Act" ran for 3 months and consisted of two motivational one-to-one sessions conducted by nurses and eight group meetings conducted by multidisciplinary teams.ConclusionsAn intervention aimed at health-related action competence was successfully developed for people with screen-detected dysglycaemia. The systematic and transparent developmental process is expected to facilitate future clinical research. The MRC model provides the necessary steps to inform intervention development but should be prioritised according to existing evidence in order to save time.

Lessons learnt from attempting to assess the evidence base for a complex intervention introduced into New Zealand general practice

Currently, in New Zealand general practice, the introduction of new initiatives is such that interventions may be introduced without an evidence base. A critical role is to respond to the challenges of chronic illness with self-management a key component. The 'Flinders Model' of self-management collaborative care planning developed in Australia has not been evaluated in New Zealand. A study was designed to assess the usefulness of this 'Model' when utilised by nurses in New Zealand general practice. This paper describes the issues and lessons learnt from this study designed to contribute to the evidence base for primary care. Assessment of problems Analysis of interviews with the nurses and the research team allowed documentation of difficulties. These included recruitment of practices and of patients, retention of patients and practice support for the introduction of the 'new' intervention. A lack of organisational capacity for introduction of the 'new' initiative alongside practice difficulties in understanding their patient population and inadequate disease coding contributed to problems. Undertaking a research study designed to contribute to the evidence base for an initiative not established in general practice resulted in study difficulties. The need for phased approaches to evaluation of complex interventions in primary care is imperative with exploratory qualitative work first undertaken to understand barriers to implementation. Collaborative partnerships between researchers and general practice staff are essential if the evidence base for primary care is to develop and for 'new' interventions to lead to improved health outcomes.

Strategies for improving patient recruitment to focus groups in primary care: a case study reflective paper using an analytical framework

BackgroundRecruiting to primary care studies is complex. With the current drive to increase numbers of patients involved in primary care studies, we need to know more about successful recruitment approaches. There is limited evidence on recruitment to focus group studies, particularly when no natural grouping exists and where participants do not regularly meet. The aim of this paper is to reflect on recruitment to a focus group study comparing the methods used with existing evidence using a resource for research recruitment, PROSPeR (Planning Recruitment Options: Strategies for Primary Care).MethodsThe focus group formed part of modelling a complex intervention in primary care in the Resources for Effective Sleep Treatment (REST) study. Despite a considered approach at the design stage, there were a number of difficulties with recruitment. The recruitment strategy and subsequent revisions are detailed.ResultsThe researchers' modifications to recruitment, justifications and evidence from the literature in support of them are presented. Contrary evidence is used to analyse why some aspects were unsuccessful and evidence is used to suggest improvements. Recruitment to focus group studies should be considered in two distinct phases; getting potential participants to contact the researcher, and converting those contacts into attendance. The difficulty of recruitment in primary care is underemphasised in the literature especially where people do not regularly come together, typified by this case study of patients with sleep problems.ConclusionWe recommend training GPs and nurses to recruit patients during consultations. Multiple recruitment methods should be employed from the outset and the need to build topic related non-financial incentives into the group meeting should be considered. Recruitment should be monitored regularly with barriers addressed iteratively as a study progresses.

Process evaluation for complex interventions in primary care: understanding trials using the normalization process model.

BackgroundThe Normalization Process Model is a conceptual tool intended to assist in understanding the factors that affect implementation processes in clinical trials and other evaluations of complex interventions. It focuses on the ways that the implementation of complex interventions is shaped by problems of workability and integration.MethodIn this paper the model is applied to two different complex trials: (i) the delivery of problem solving therapies for psychosocial distress, and (ii) the delivery of nurse-led clinics for heart failure treatment in primary care.ResultsApplication of the model shows how process evaluations need to focus on more than the immediate contexts in which trial outcomes are generated. Problems relating to intervention workability and integration also need to be understood. The model may be used effectively to explain the implementation process in trials of complex interventions.ConclusionThe model invites evaluators to attend equally to considering how a complex intervention interacts with existing patterns of service organization, professional practice, and professional-patient interaction. The justification for this may be found in the abundance of reports of clinical effectiveness for interventions that have little hope of being implemented in real healthcare settings.

A lesson learnt: the importance of modelling in randomized controlled trials for complex interventions in primary care

The Randomised Controlled Trial (RCT) is recognised as the 'gold standard' in quantitative research. However RCTs testing health care interventions can be difficult to design and implement. Health care interventions are often complex in themselves and are always applied in complex settings. Such interventions require a process of careful 'modelling' to maximize the chances of successful trials that will add to knowledge. To describe the terms 'complex' and 'modelling' as used in the setting of randomised controlled trials of complex interventions. To give a practical example of an RCT involving a complex intervention applied in a health care setting to illustrate how this might take place in practice. We describe an RCT designed and conducted by the authors. We then use our trial as an example to illustrate how complex interventions such as ours might benefit from modelling during the design of the intervention and the setting within which the intervention is to be tested. Our project was designed and tested before current guidance on complex interventions was published; our RCT was therefore not 'modelled' but was based on the outcome of a single quantitative pilot study. As part of our study we ran a parallel qualitative study, which highlighted several areas of complexity both in our intervention, and in the setting within which we applied it. In this paper we show how modelling might have allowed us to recognise these complexities at an early stage and might therefore have resulted in a study more likely to have demonstrated useful outcomes. Careful modelling of complex interventions is an essential step in designing trials of innovations in health care and health care services. Such a process ensures that interventions fit with and reflect the complexities of the settings within which interventions will be applied, and should ensure that the outcomes chosen are those most appropriate to demonstrate any benefits or risks.