Outpatient interdisciplinary multimodal pain therapy for chronic musculoskeletal pain: examining patient-reported and performance-based correlates of treatment outcomes

Objectives This retrospective analysis of real-world clinical data aimed to evaluate interdisciplinary, multimodal pain therapy (IMPT) delivered in an outpatient clinic for individuals with chronic musculoskeletal pain. The primary objectives were to assess improvements in pain intensity and pain-related disability, and to examine theory- and evidence-based correlates of these outcomes, including mental and physical health parameters.Methods A cohort of 308 patients underwent a four-week IMPT, which included exercise, manual therapy, and cognitive behavioural therapy. Pain intensity and disability (Chronic Pain Grade), habitual well-being (Marburg Questionnaire on Habitual Well-being), mental and physical health (Veterans RAND 12), depressive symptoms, anxiety, and stress (Depression Anxiety Stress Scale) were assessed with self-report questionnaires approximately two months before and six months after IMPT. Physical function was assessed with performance-based measures including the stair climb test, a stability, sensorimotor regulation and symmetry test and the prone bridge test at the beginning and end of the treatment. Data were analysed by dependent samples t-tests and multiple linear regressions.Results Six months post-treatment, patients showed reductions in pain intensity (d = .95) and disability (d = .75). Improvements in depression, anxiety, stress, habitual well-being, physical health, and physical function were observed, with effect sizes ranging from small to large. Regression analysis showed that improvements in self-reported habitual well-being and physical health were associated with changes in pain intensity and disability. However, this was not the case for changes in performance-based physical function or changes in psychological risk factors (i.e. depressive symptoms, stress).Discussion The results demonstrate that pain reductions after IMPT are more strongly associated with changes in subjective perceptions of health and habitual well-being than with performance-based indicators. However, further research is needed to draw conclusions about causality and to account for other potential contributing factors, such as treatment adherence, pain catastrophising, and self-efficacy.