Reporting and synthesis practices in barriers and facilitators reviews: a methodological systematic review

Abstract Background An increasing number of systematic reviews set out to identify and synthesise research on barriers to and facilitators of the achievement of various outcomes. Yet, this type of review has been criticised for relying on aggregative synthesis approaches (such as vote counting), and for generating overly simplistic representations of complex social issues. We aimed to describe and appraise the reporting and synthesis practices used in recently published barriers and facilitators reviews in public health. Methods We did a methodological systematic review of reviews, using the following databases: ABI/INFORM Global, Applied Social Sciences Index and Abstracts (ASSIA), CINAHL, Embase, Global Health, International Bibliography of the Social Sciences (IBSS), Medline, PAIS Index, PsycINFO, Social Science Database, and Sociology Database. All English-language peer-reviewed systematic reviews that synthesised either primary or secondary research on barriers and facilitators in a health-related context were eligible for inclusion. We designed the search string to include an exhaustive list of synonyms for "barrier(s)", "facilitator(s)", and "systematic review". We restricted our search results to reviews from Nov 1, 2017, to Nov 30, 2018. Our protocol was prospectively registered in PROSPERO (CRD42018112361). Findings 100 reviews were identified. We found a high degree of variation in the synthesis and categorisation practices used in barriers and facilitators reviews, with most reviews using aggregative (rather than interpretive) synthesis approaches. The findings echo common critiques of this review type, including concerns associated with reducing complex issues to simplified, discrete factors. Few reviews critically investigated the potential dynamic features and contextual variability of, and interrelationships between, identified factors. Although several papers highlighted the complexity of barriers and facilitators, this was usually mentioned in passing rather than systematically analysed or discussed in depth. Analysis of the minority of reviews that included explicit discussion of the barriers and facilitators approach revealed some common themes. These issues tended to be either conceptual/definitional (eg, ideas about the interrelationships and overlap between factors) or methodological/practical (eg, challenges related to the aggregation of heterogeneous research). Interpretation Barriers and facilitators reviews can enhance both their academic contribution and effect on policy and practice by clearly defining their constructs of analysis, explicitly describing how factors are extracted and subsequently synthesised, and providing critical reflection on the contextual variability and reliability of identified factors. Funding None.