Effectiveness of behavioural interventions incorporating motivational interviewing to increase physical activity: a systematic review and meta-analysis

Objective: To evaluate the effectiveness of behavioural interventions incorporating motivational interviewing (MI) to increase physical activity (PA) in adult populations. Study design: Systematic review and meta-analysis of randomised controlled trials. Study selection: Asearch of seven databases for studies published from inception to 1st March 2023 was conducted for randomised controlled trials (RCTs) comparing a behavioural intervention incorporating MI with a comparator that did not include MI on PA outcomes in adults. The outcomes of interest were differences in change in quantitative measures of total PA, moderate to vigorous PA (MVPA), and sedentary time. Data extraction and synthesis: Two reviewers extracted data and assessed risk of bias. Population characteristics, intervention components, comparison groups, and outcomes of studies were summarised. Overall main effects were conducted using random effects meta-analyses to report standardised mean differences and 95%CI. Differential effects based on duration of follow-up, comparator type, intervention duration, and participant disease/health condition status were also examined. Results: 129 papers reporting 97 randomised controlled trials examining 27,811 participants with 105 comparisons were included. Low certainty evidence showed interventions incorporating MI were superior to comparators (SMD 0.45, 95% CI: 0.33 to 0.65) for total PA, equivalent to 1323 extra steps/day .There was very low certainty evidence for interventions incorporating MI for increasing MVPA (SMD 0.45, 95% CI: 0.19 to 0.71, equivalent to 95 extra min/week) and reducing sedentary time (SMD -0.58, 95% CI: -1.03 to -0.14, equivalent to -51 min/day) compared to interventions that did not include MI. There was no evidence of a difference in any outcome when compared to interventions of similar intensity without MI. The magnitude of effect diminished over time and there was no evidence of an effect of MI beyond 1 year. Most interventions involved patients with a specific health condition and there was no evidence of an effect of MI to increase MVPA or decrease sedentary time in general population samples. Conclusions: The certainty of the evidence on using MI as part of complex behavioural intervention for promoting total PA is low and for MVPA and sedentary time is very low. The totality of evidence suggests whilst interventions incorporating MI increase physical activity and decrease sedentary behaviour, there was no evidence of a difference in studies where the effect of MI could be isolated. The effectiveness wanes over time, with no evidence of a benefit of MI to increase physical activity beyond 1 year. Systematic review registration: PROSPERO CRD42020219881