Do baseline patient reported outcome measures predict changes in self-reported function, following a chronic pain rehabilitation programme?

Background: Interdisciplinary pain management programmes, based on cognitive-behavioural principles, aim to improve physical and psychological functioning and enhance self-management in people living with chronic pain. Currently there is insufficient evidence about whether psychological, biological or social factors are predictive of positive outcomes following pain rehabilitation. This study aims to evaluate predictors of change in Brief Pain Inventory - pain interference score (BPI) in a clinical data set to determine whether age, sex and baseline outcome measures are predictive of improvement in pain interference following pain rehabilitation. Methods: A retrospective, pragmatic observational analysis of routinely collected clinical data in two pain rehabilitation programmes, Balanced Life Programme (BLP) and Get Back Active (GBA) was conducted. Standard regression and hierarchical regression analyses were used to identify predictors of change to assess temporal changes in BPI. Responder analysis was also conducted. Results: Standard regression analyses of 208 (BLP) and 310 (GBA) patients showed that higher baseline BPI and better physical performance measures predicted better improvement in BPI across both programmes. Hierarchical regression showed that age and sex accounted for 2.7% (BLP) and 0.002% (GBA) of the variance in change in BPI. After controlling for age and sex, the other measures explained an additional 23% (BLP) and 19% (GBA) of the variance, p = < .001 where BPI and physical performance measures were consistently statistically significant predictors, p < .05. Responder analysis also showed that pain interference and physical performance were significantly associated with improvement (p = < .0005). Conclusions: The combination of high self-reported pain interference and better physical performance measures may be a useful indicator of who would benefit from interdisciplinary rehabilitation. Further validation of the results is required.