Group membership and staff turnover affect outcomes in group CBT for persistent pain.

The effects of two contextual factors, group membership and staff turnover, on the outcome of group cognitive behavioral therapy (CBT) for persistent pain were investigated. The data came from end of treatment and 1 month follow-up assessments of 3050 individuals who attended an intensive group programme over 16 years. Intraclass correlations (ICC) showed significant intragroup effects on self-efficacy (ICC=0.16 at end of treatment; 0.12 at 1 month), catastrophizing (ICC=0.06; 0.13) and distance walked (ICC=0.20; 0.19). This underlines the importance of modelling group membership when analyzing data from group interventions. Linear regression showed that high periods of staff turnover were significantly related to poorer outcomes on self-efficacy and distance walked at end of treatment, with the effect on self-efficacy persisting to 1 month follow-up. Having demonstrated significant contextual effects in an existing data set, further research is needed to explore the mechanisms by which these effects operate.