To what extent do interventions target barriers to change? A novel systematic review method

Abstract

Background: Systematic reviews often show variable intervention effects. In behaviour change interventions variation might be explained by differences in intervention components (e.g. behaviour change techniques [BCTs], modes of delivery), or barriers targeted. Most behaviour change reviews synthesise evidence of effectiveness, whereas some use theoretical frameworks to synthesise evidence about reported barriers/enablers to change. However, these two methodological approaches have not been integrated in a systematic review context. This study combines the two approaches to review the literature on attendance for diabetic retinopathy screening to address whether existing interventions target identified barriers to change. Method: Three stages are proposed. Stage 1: Systematically identify reports of randomised controlled trials aiming to increase diabetic retinopathy screening attendance; apply an established BCT taxonomy to code intervention descriptions into BCTs targetting screening attendance; and explore heterogeneity in effect size using various meta-analytic methods to identify BCTs associated with effectiveness. Stage 2: Systematically identify published/grey literature reporting barriers/enablers to attendance for diabetic retinopathy screening; code barriers/enablers according to the Theoretical Domains Framework (TDF). Stage 3: Map BCTs (from stage 1) with theoretical domains (from stage 2) using established techniques (i.e. BCT/TDF mapping matrices), to identify the extent to which the interventions target the identified barriers/enablers. Discussion: This methodological approach can be used to evaluate whether ‘active components’ of existing interventions actually target factors proposed to mediate change. This approach could help further explain variation in intervention effects. Findings will inform recommendations for future research in terms of evidence-based intervention components that are likely to maximise effectiveness.