Motivational interviewing to increase physical activity in people with chronic health conditions: a systematic review and meta-analysis.

OBJECTIVE: A systematic review and meta-analysis of randomized controlled trials to determine if motivational interviewing leads to increased physical activity, cardiorespiratory fitness or functional exercise capacity in people with chronic health conditions. DATA SOURCES: Seven electronic databases (MEDLINE, PsychINFO, EMBASE, AMED, CINHAL, SPORTDiscus and the Cochrane Central Register of Controlled trials) were searched from inception until January 2014. TRIAL SELECTION: Two reviewers independently examined publications for inclusion. Trials were included if participants were adults (>18 years), had a chronic health condition, used motivational interviewing as the intervention and examined physical activity, cardiorespiratory fitness or functional exercise capacity. DATA EXTRACTION: Two reviewers independently extracted data. Risk of bias within trials was assessed using the Physiotherapy Evidence Database Scale. DATA SYNTHESIS: Meta-analyses were conducted with standardized mean differences and 95% confidence intervals (CIs) were calculated. The Grades of Recommendation, Assessment, Development and Evaluation approach was used to evaluate the quality of the evidence. RESULTS: Eleven publications (of ten trials) were included. There was moderate level evidence that motivational interviewing had a small effect in increasing physical activity levels in people with chronic health conditions relative to comparison groups (standardized mean differences = 0.19, 95% CI 0.06 to 0.32, p = 0.004). Sensitivity analysis based on trials that confirmed treatment fidelity produced a larger effect. No conclusive evidence was observed for cardiorespiratory fitness or functional exercise capacity. CONCLUSION: The addition of motivational interviewing to usual care may lead to modest improvements in physical activity for people with chronic health conditions.