Examining the association between group context effects and individual outcomes in an interdisciplinary group-based treatment for chronic pain based on acceptance and commitment therapy

Helen R Gilpin; Soravis Ratanachatchuchai; David Novelli; Lance M McCracken; Whitney Scott

doi:10.1177/20494637211073012

Examining the association between group context effects and individual outcomes in an interdisciplinary group-based treatment for chronic pain based on acceptance and commitment therapy

Br J Pain. 2022 Aug;16(4):420-432. doi: 10.1177/20494637211073012. Epub 2022 Mar 4.

Authors

Helen R Gilpin¹, Soravis Ratanachatchuchai², David Novelli¹, Lance M McCracken³, Whitney Scott^{1

2}

Affiliations

¹ INPUT Pain Management Unit, Guy's and St Thomas' NHS Foundation Trust, London, UK.
² Health Psychology Section, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK.
³ Department of Psychology, Uppsala University, Uppsala, Sweden.

Abstract

Background: Although cognitive-behavioural treatments for chronic pain are delivered in groups, there is little research investigating group effects in these treatments.

Purpose: The aim of this study was to investigate associations between group composition variables at the start of treatment and individual outcomes following intensive interdisciplinary treatment for pain based on Acceptance and Commitment Therapy.

Methods: This was a secondary analysis of routinely collected observational data. Five-hundred and sixteen patients completed a standard set of demographic, pain-related and psychosocial measures at pre- and post-treatment. Intracluster correlations (ICCs) were computed to examine the clustering of outcomes within groups and multilevel models explored the association between group composition variables and individual level outcomes.

Results: The ICCs for pain intensity (0.11) and interference (0.09) suggested that multilevel models were warranted for these outcomes, while a multilevel model for post-treatment depression (ICC = 0.04) was not warranted. Group percentage of participants receiving disability benefits and group mean pain intensity at pre-treatment were significantly positively associated with individual level pain intensity at post-treatment, controlling for pre-treatment individual level pain intensity. Group mean pain intensity at pre-treatment was the only group variable that significantly predicted post-treatment pain interference at the individual level. Psychosocial group composition variables were not significantly associated with individual level outcomes.

Conclusion: Given the limited predictive utility of group composition variables in the current study, future research should undertake direct assessment of group level therapeutic and countertherapeutic processes to advance understanding of who benefits from group treatments for pain and how. As the variance in outcomes accounted for by group clustering was relatively small and significant within groups variance remained, research is also needed to further understand individual level factors that influence cognitive-behavioural treatment outcomes for pain.

Keywords: acceptance and commitment therapy; chronic pain; group context; group therapy; pain management.