Long-Term Effects of a Chronic Pain Management Program ('PAIN CAMP') on Refractory Chronic Pain Classified by ICD-11:...

Chronic pain is associated with functional disability and reduced work participation. This study aimed to evaluate the long-term effects of a multidisciplinary chronic pain management program adapted to the Japanese healthcare system on work-related status, pain-related assessments, and physical function in patients with chronic pain classified under ICD-11.

One hundred patients participated in a 5-week program comprising exercise therapy, cognitive behavioral therapy (CBT), pain education, and nature-based activities. The program was delivered in a mixed inpatient-outpatient format, with all participants completing both components as part of an integrated program, allowing participants to practice and apply pain coping skills in their daily lives between sessions. Outcomes were assessed at baseline, post-treatment, 3, and 12 months. Self-reported assessments included pain severity (NRS), self-efficacy (PSEQ), catastrophizing (PCS), disability (PDAS), quality of life (EQ-5D-3L), anxiety/depression (HADS), and sleep quality (PSQI). Physical function was assessed through standardized tests. Missing data were addressed using multiple imputations, and repeated-measures ANOVA with Bonferroni correction was used to examine changes over time. Effect sizes (Cohen's d) were calculated.

All self-reported assessments improved significantly post-treatment and were sustained at 3 and 12 months (p < 0.05, Bonferroni-corrected). Effect sizes ranged from small to large, with particularly large effects observed for self-efficacy, catastrophizing, and several physical functions. Among those not working at baseline, 66% had returned to work at 3 months and 81% at 12 months. No significant group × time interaction was observed between chronic primary and secondary pain groups, although baseline anxiety levels (HADS-A) were higher in the chronic primary group.

Our multidisciplinary chronic pain management program demonstrated significant effectiveness in enhancing long-term outcomes and facilitating return-to-work in patients with refractory chronic pain, including chronic primary pain.