Exploring the mechanisms of change in the chronic disease self-management programme: secondary analysis of data from a randomised controlled trial.

The Chronic Disease Self-Management Programme (CDSMP) has been shown to be clinically and cost effective; however the specific mechanisms by which benefits are achieved are not well understood. We investigate what aspects of the course are associated with different outcomes.Post-hoc analysis of data from participants in a randomised controlled trial of the CDSMP using evaluations after 6 months for all patients and longer term outcomes at 12 months for a sub-set of patients. Data were analysed using univariate and multivariate regressions.All course quality variables apart from the venue predicted satisfaction with CDSMP. The best predictors were ratings of the group process and course content. Group process was also significantly associated with self-care behaviour and long-term group outcomes (such as maintaining contact). Few associations between course ratings and patient health outcomes were found.The most consistent predictor of CDSMP outcomes was the rating of the group process, highlighting the importance of group dynamics, however the complexity of mechanisms by which the CDSMP works cautions against giving primacy to any single factor.Taking measures to ensure group processes are of high quality and effective within CDSMP are important in maximising patient satisfaction and self-care behaviour change.