Clinical predictors of immediate response to a multimodal inpatient programme for chronic refractory musculoskeletal pain syndromes-a cross-sectional study.

Objectives: Chronic pain (CP) affects approximately 20% of the global population, leading to significant disability and economic burden. Multimodal programmes (MMPs) are the most effective short-term interventions for managing musculoskeletal chronic pain syndromes (MCPS). However, patient characteristics influence treatment response, requiring personalized approaches. This study aims to identify clinical, social and psycho-behavioural predictors of immediate response to a 2-week inpatient MMP for refractory MCPS.

Methods: A cross-sectional study analysed 207 MCPS patients who completed an MMP at CHUV Lausanne, Switzerland, from March 2018 to November 2022. Validated questionnaires assessed pain severity, impact, kinesiophobia, catastrophizing and other factors before and after the programme. Univariate and multivariate analyses identified predictors of treatment response.

Results: Significant improvements were observed in 9 out of 12 outcomes, including pain severity (P = 0.01), pain impact (P < 0.01), disability (P = 0.14), kinesiophobia (P<0.001) and catastrophizing (P < 0.001). Non-specific low-back pain, catastrophizing at entry, biomechanical disorders and psychiatric conditions were identified as key predictors of treatment response, respectively influencing 4, 3, 3 and 2 over 9 outcome measures in multivariable analysis. Non-specific low-back pain was linked to worse outcomes, whereas reductions in catastrophizing correlated with improved pain severity and kinesiophobia. Socioeconomic factors, such as disputes over disability financial aid, also influenced outcomes.

Conclusion: This study confirms a modest yet significant immediate benefit of MMP for patients with refractory MCPS and provided a deeper insight into the predictors of treatment outcomes and their influence on various outcome measures. Further longitudinal studies are needed to confirm these findings and explore underlying mechanisms.