Objectives
Chronic pain causes loss of workability, and pharmacological treatment is often not sufficient, whereas psychosocial treatments may relieve continual pain. This study aimed to investigate the effect of peer group management intervention among patients with chronic pain.

Methods
The participants were 18–65-year-old employees of the Municipality of Helsinki (women 83%) who visited an occupational health care physician, nurse, psychologist, or physiotherapist for chronic pain lasting at least 3 months. An additional inclusion criterion was an elevated risk of work disability. Our study was a stepped wedge cluster, randomized controlled trial, and group interventions used mindfulness, relaxation, cognitive behavioral therapy, and acceptance and commitment therapy. We randomized sixty participants to either a pain management group intervention or to a waiting list with the same intervention 5 months later. After dropouts, 48 employees participated in 6 weekly group meetings. We followed up participants from groups A, B, and C for 12 months and groups D, E, and F for 6 months. As outcome measures, we used the pain Self-Efficacy Questionnaire, the number of areas of pain, the visual analog scale of pain, and the pain self-efficacy. We adjusted the results before and after the intervention for panel data, clustering effect, and time interval.

Results
The peer group intervention decreased the number of areas of pain by 40%, from 5.96 (1–10) to 3.58 (p < 0.001), and increased the pain self-efficacy by 15%, from 30.4 to 37.5 (p < 0.001). Pain intensity decreased slightly, but not statistically significantly, from 7.1 to 6.8.

Conclusions
Peer group intervention for 6 weeks among municipal employees with chronic pain is partially effective. The number of areas of pain and pain self-efficacy were more sensitive indicators of change than the pain intensity. Any primary care unit with sufficient resources may implement the intervention.