Interdisciplinary rehabilitation in patients with chronic pain : prognostic factors and effectiveness

Sammanfattning: Interdisciplinary multimodal pain rehabilitation (IMPR) is currently considered best practice for combatting chronic pain. However, it is believed that health-related outcomes could be improved with more adequately tailored treatment programs, but consensus of what grounds these adaptations should be based on is yet to be reached. Well-powered evaluations of naturalistic, real-world practices provide an evidence base for the evaluation of important characteristics that may facilitate the informed development of IMPR. The aim of the present work was to meta-synthesize existing evidence and add new data to the body of published evidence on prognostic factors for a positive outcome in patients receiving rehabilitation for chronic pain. An additional aim was to evaluate the effectiveness of different IMPR program durations on health-related quality of life in this major patient group. Methods: Published international evidence of prognostic factors for physical functioning after IMPR was evaluated through a systematic review and meta-analyses (Study I), followed by the investigation of the inter-rater reliability of the Quality in Prognostic Studies tool (QUIPS), used in the Risk of Bias assessment (Study II). Prognostic factors (Study III) and effectiveness (Study IV) of Swedish pain specialist IMPR on physical and mental functioning and related measures of disease impact were investigated using large-scale nationwide data obtained from the Swedish Quality Registry for Pain Rehabilitation. Results: Meta analyses showed, with moderate to low levels of evidence, that better physical functioning at follow-up was predicted by high levels of self-reported functioning, low levels of emotional distress and cognitive-behavioral risk factors, and high levels of cognitive- behavioral protective factors. Pain-related factors (intensity and chronicity) were not associated. Weak to moderate inter-rater agreement emerged for QUIPS, and suggestions for improving the inter-rater agreement and functionality were presented. Swedish registry data showed the most important prognostic factors were retaining a connection with work, having high optimistic treatment expectations, sense of control, and less interference from pain. Pain itself was of secondary significance. Also for improvement of physical functioning, better initial mental wellbeing was of importance, while for mental functioning the opposite emerged. Results on within-group effectiveness showed improvements on all outcomes, while no between-group comparison emerged on short (4-9 wks) vs. moderate (10 wks) vs. long (11-18 wks) IMPR program duration. In summary, evidence for prognostic factors was identified, providing suggestions for the targeting of modifiable factors in clinics and in future clinical trials. Clearly, the quality assessment of published results needs systematic consensus work between assessors. Work connection, treatment expectations, levels of physical and emotional health, and coping strategies played an important prognostic role but were not consistent for physical and emotional functioning, suggesting a complex prognostic picture for the overall understanding of improvement. Finally, IMPR is effective across a biopsychosocial specter, but treatment duration seems not to play an important role.