Longitudinal Outcome Evaluations of Interdisciplinary Multimodal Pain Treatment Programs for Patients With Chronic Primary Musculoskeletal Pain: A Living Systematic Review

Background and Objectives: Interdisciplinary Multimodal Pain Treatment (IMPT), grounded in the biopsychosocial model, is strongly recommended for patients with chronic primary pain. A base review found that IMPT participation leads to sustained improvements in wellbeing, but substantial heterogeneity in program dose and content limited conclusions about optimal design. This first update as a living systematic review (LSR) aimed to assess the long-term effects (= 12 months post-treatment) of IMPT for chronic primary musculoskeletal pain and explore patterns in treatment effectiveness to inform program optimization. Databases and Data Treatment: This LSR updated the base review's systematic search (January 2025) in Medline, Embase, PsycInfo and Cinahl. Eligible studies included adults with chronic primary musculoskeletal pain who completed IMPT and were followed for at least 12 months. Two reviewers independently screened studies, extracted data and assessed risk of bias. Standardised mean changes were calculated for nine outcome domains plus health-related quality of life (HRQoL). Exploratory subgroup analyses examined intervention-specific factors. Results: Eighty-nine articles (110 cohorts) were included. Significant pre- to post-treatment improvements occurred in 83% of cohorts and were generally maintained at follow-up. HRQoL, newly analysed, improved in 86% of 30 reporting cohorts. Substantial to high heterogeneity (I² > 61.42%) reflected differences in program design. Exploratory findings suggest that individual formats, using high tailoring and limiting treatment to = 30 contact hours may yield the most consistent benefits. Conclusions: IMPT programs provide durable improvements in physical, emotional and social functioning, among which HRQoL, though the evidence remains of very low certainty and program variability persists. Significance: This LSR reaffirms the effectiveness of IMPT in improving physical and psychological outcomes in individuals with chronic primary pain, and expands the evidence base by incorporating HRQoL as a novel outcome. HRQoL improvement underscores the long-term effectiveness of IMPT in improving overall well-being. Highly tailored, individually delivered IMPT programs that integrate recent innovations and are under 30 h in duration appear most effective in reducing pain-related disability and improving health-related quality of life.