Mechanisms associated with increased physical activity in patients undergoing self-management behaviour modification in the randomised PHYSACTO trial

INTRODUCTION: In this analysis of the PHYSACTO® study, we assessed the efficacy of a self-management behaviour modification (SMBM) programme to improve physical activity (PA) levels, and the extent to which effects were mediated by readiness to change, motivation and confidence. METHODS: PHYSACTO® was a randomised, partially double-blind, parallel-group, 12-week trial to evaluate the effects of treatment on exercise capacity and PA. COPD patients received placebo, tiotropium 5 µg or tiotropium/olodaterol 5/5 µg, with or without exercise training, all with an SMBM intervention (the Living Well with COPD programme). Changes were assessed in readiness to change (stage of change visual analogue scale [VAS]), motivation (Treatment Self-Regulation Questionnaire [TSRQ]) and confidence (Perceived Competence Scale [PCS]) to engage in PA. RESULTS: PA was increased in all patients with complete PA data at Week 12 (n=262; +6038 steps·week(−1), p<0.001). Significant increases were observed in patients' readiness to change (VAS 0.7 [0.6–0.8]), autonomous regulation (TRSQ 0.2 [0.1–0.3]) and confidence (PCS 0.5 [0.3–0.6]) (all p<0.01). Of note, 23% of the total effect of SMBM on steps·week(−1) was found to be mediated by increases in readiness to change, 5% by TSRQ autonomous regulation and 12% by PCS. CONCLUSION: Our study demonstrated that an SMBM programme delivered to COPD patients increased PA, mediated by an improvement of three key hypothesised mechanisms of change: readiness to change, autonomous motivation and confidence. For the first time, this study shows that an SMBM programme can be successful in altering the mechanisms of change targeted by the intervention.