Behaviour change interventions to improve physical activity in adults: a systematic review of economic evaluations

Background: Behaviour change interventions can result in lasting improvements in physical activity (PA). A broad implementation of behaviour change interventions are likely to be associated with considerable additional costs, and the evidence is unclear whether they represent good value for money. The aim of this study was to investigate costs and cost-effectiveness of behaviour change interventions to increase PA in community-dwelling adults. Methods: A search for trial-based economic evaluations investigating behaviour change interventions versus usual care or alternative intervention for adults living in the community was conducted (September 2023). Studies that reported intervention costs and incremental cost-effectiveness ratios (ICERs) for PA or quality-adjusted life years (QALYs) were included. Methodological quality was assessed using the Consensus Health Economic Criteria (CHEC-list). A Grading of Recommendations Assessment, Development and Evaluation style approach was used to assess the certainty of evidence (low, moderate or high certainty). Results: Sixteen studies were included using a variety of economic perspectives. The behaviour change interventions were heterogeneous with 62% of interventions being informed by a theoretical framework. The median CHEC-list score was 15 (range 11 to 19). Median intervention cost was US$313 per person (range US$83 to US$1,298). In 75% of studies the interventions were reported as cost-effective for changes in PA (moderate certainty of evidence). For cost per QALY/gained, 45% of the interventions were found to be cost-effective (moderate certainty of evidence). No specific type of behaviour change intervention was found to be more effective. Conclusions: There is moderate certainty that behaviour change interventions are cost-effective approaches for increasing PA. The heterogeneity in economic perspectives, intervention costs and measurement should be considered when interpreting results. There is a need for increased clarity when reporting the functional components of behaviour change interventions, as well as the costs to implement them.