Behaviour change techniques that constitute effective planning interventions to improve physical activity and diet behaviour for people with chronic conditions: a systematic review

Objectives Action planning is a brief and effective behaviour change technique (BCT) to improve physical activity (PA) and diet behaviour (DB). This study aimed to identify critical BCTs and mechanisms of action (MoAs) to interpret the effectiveness of planning interventions based on the Health Action Process Approach (HAPA) model. Design Systematic review. Data sources PubMed, Web of Science, CINAHL (EBSCO), PsycINFO (EBSCO), Psychology and Behavioural Sciences Collection (EBSCO), psyARTICLES and Medline were searched for studies from January 1990 to September 2021 published in English. Eligibility criteria Experiment involving action planning intervention to improve PA or DB in community-dwelling adult patients with chronic conditions. Data extraction and synthesis Two reviewers independently coded the planning interventions into BCT combinations and MoA assemblies. Outcome was dichotomised according to the statistical power and Cohen's d. The Cochrane risk of bias assessment tool and the Risk of Bias in Nonrandomized Studies-of Interventions assessment tool were used to assess the quality of randomised controlled trials (RCTs) and non-RCTs, respectively. Results From the 52 included studies, 46 BCTs were identified and linked to 21 MoAs. Long-term facilitators for planning intervention included 'self-monitoring of behaviour', 'problem solving', 'instruction on how to perform the behaviour' and 'adding objects to the environments'. The three most frequently occurring MoAs were 'intention', 'behavioural regulation', 'beliefs about capabilities'. The effective intervention groups had higher MoA scores that corresponded to the HAPA model constructs than the ineffective groups. Conclusions The findings from this review may inform scientific and effective planning intervention designs for community-dwelling people with chronic conditions in the future. PROSPERO registration number CRD42021241227.