Feelings of fatigue, annoyance or anger, or hostility predict improvement in pain-related disability following an interdisciplinary multimodal pain treatment program for chronic musculoskeletal pain: a longitudinal cohort study

Background: Knowledge about predictive factors for treatment response is essential to stratify patients with chronic musculoskeletal pain (CMP) to the most effective treatment program. Sociodemographic, functional and pain-related factors are well-researched, but less is known about the predictive role of psychological factors. Objective: This study aimed to explore the predictive value of understudied multi-dimensional symptoms for pain-related disability reduction following an interdisciplinary multimodal pain treatment program (IMPT) for CMP. Methods: A dataset of 653 patients with CMP who attended either a 10 or 20-week IMPT at the Clinics in Rehabilitation in the Netherlands was analyzed. The data was collected by questionnaires at screening, after 10 weeks, and after 20 weeks when applicable. The treatment effect on disability was assessed using the Pain Disability Index (PDI). The predictive value of the Tampa Scale of Kinesiophobia (TSK), Checklist Individual Strength (CIS), Beck Depression Inventory (BDI), Utrechtse Coping List (UCL), and Symptom Checklist-90 (SCL-90) was assessed. Results: Pre-treatment CIS (p =.03), subcategory “Expression of emotion” of the UCL (p =.01), and subcategory “Hostility” of the SCL-90 (p =.02) scores were predictive for treatment success. Additionally, a decrease of 11.7 points on the total PDI score was found following a 20 week IMPT. Conclusions: These results suggest that an IMPT, built according to the biopsychosocial model, will result in a greater reduction of pain disability in patients who report more severe fatigue, more annoyance or anger, or more signs of hostility prior to starting the treatment.