Optimisation of complex health interventions prior to a randomised controlled trial: a scoping review of strategies used

Abstract

Background: Many complex intervention trials fail to show an intervention effect. Although this may be due to genuine ineffectiveness, it may also be the result of sub-optimal intervention design, implementation failure or a combination of these. Given current financial constraints and the pressure to reduce waste and increase value in health services research, pre-trial strategies are needed to reduce the likelihood of design or implementation failure and to maximise the intervention's potential for effectiveness. In this scoping review, we aimed to identify and synthesise the available evidence relating to the strategies and methods used to 'optimise' complex interventions at the pre-trial stage.

Methods: We searched MEDLINE, CINAHL, AMED, PsycINFO and ProQuest Nursing & Allied Health Source for papers published between January 2000 and March 2015. We included intervention development and optimisation studies that explored potential intervention weaknesses and limitations before moving to a definitive randomised controlled trial (RCT). Two reviewers independently applied selection criteria and systematically extracted information relating to the following: study characteristics; intervention under development; framework used to guide the development process; areas of focus of the optimisation process, methods used and outcomes of the optimisation process. Data were tabulated and summarised in a narrative format.

Results: We screened 3968 titles and 231 abstracts for eligibility. Eighty-nine full-text papers were retrieved; 27 studies met our selection criteria. Optimisation strategies were used for a range of reasons: to explore the feasibility and acceptability of the intervention to patients and healthcare professionals; to estimate the effectiveness and cost-effectiveness of different combinations of intervention components; and to identify potential barriers to implementation. Methods varied widely across studies, from interviews and focus groups to economic modelling and probability analysis.

Conclusions: The review identifies a range of optimisation strategies currently used. Although a preliminary classification of these strategies can be proposed, a series of questions remain as to which methods to use for different interventions and how to determine when the intervention is ready or 'optimised enough' to be tested in a RCT. Future research should explore potential answers to the questions raised, to guide researchers in the development and evaluation of more effective interventions.

Keywords: Acceptability; Complex interventions; Effectiveness; Intervention development; Modelling; Optimisation; Pre-trial; Scoping review.

Fig. 1

Key phases of the main frameworks that currently provide guidance on conducting pre-trial testing. Shaded boxes indicate ‘optimisation’ stages. These frameworks have all been employed, to varying degrees, to define potential limitations and weaknesses of the intervention, in order to refine the intervention before moving to the trial stage.

Fig. 2

Iterative approach followed to conduct this scoping review

Fig. 3

Study flow diagram. (In asterisk) Duplicates between databases searched simultaneously were removed automatically, whereas further duplicates were retrieved manually

Fig. 4

Representative examples of the HTA applied to Gray et al. [27]. Gray et al. [27] reported on the development and optimisation of the Football Fans in Training programme (p-FFIT), an intervention to help men lose weight, become more active and adopt healthier eating habits. In the programme development phase, an expert multidisciplinary group led the development of the pilot programme. The aim of the optimisation phase was to inform final modifications to the programme prior to full-scale evaluation. This phase involved a series of qualitative studies to explore the programme delivery from the viewpoints of both participants and coaches. These include participant feedback forms, participant focus groups, telephone or face-to-face interviews with non-completers, coach focus groups and interviews, a coach workshop and programme session observations. The coding frame was based on perceived acceptability/satisfaction, views on likely effectiveness of programme components and suggestions for changes. The process evaluation confirmed that the p-FFIT was highly acceptable to both participants and coaches. A number of potential areas for improvement were identified and, where possible, incorporated into the optimised FFIT intervention