Outpatient interdisciplinary multimodal pain treatment programme for patients with chronic musculoskeletal pain: a longitudinal cohort study

Purpose: To describe the outcomes of an interdisciplinary multimodal pain treatment (IMPT) for chronic musculoskeletal pain (CMP) patients up until 12 months post-treatment. Materials and Methods: Data were gathered during routine clinical practice during a 3-year period (2019–2021) at six Dutch rehabilitation centres. Assessments included patient-reported outcome measures for multiple domains including disability, pain and fatigue. Longitudinal data were analysed using repeated-measures models and by quantifying responder rates. Results: Included were 2309 patients with a mean age of 43.7 (SD 12.9) years, of which 73% female. All outcomes showed significant improvements at each timepoint. At discharge, large effect sizes were found for disability, average and worst pain, fatigue and health-related quality of life. Improvements were largely sustained at 12-months. Relatively large proportions of patients had clinically relevant improvements after treatment (pain-related disability: 60%; average pain: 52%; worst pain: 37.4%; work capacity: 50%; concentration: 50%; fatigue: 46%). Patients who received a treatment extension showed further improvements for all outcome measures, except average pain. Conclusions: At group level, all outcomes significantly improved with mainly large effect sizes. The results were mostly sustained. The proportion of patients showing clinically relevant improvements tends to be larger than previously reported for mixed CMP patients.