Effectiveness of medical rehabilitation in persons with back pain–lessons learned from a German cohort study

Purpose: Evidence for health-related effects of German medical rehabilitation programs for back pain is inconclusive. This cohort study aimed to examine the effectiveness of medical rehabilitation in residents with back pain (German Clinical Trial Register: DRKS00011554). Material and methods: A sample of 45 000 people aged 45–59 years was randomly drawn from two pension agencies. We used propensity score matching to compare persons with back pain who completed a medical rehabilitation program with similar untreated subjects. Questionnaire data were assessed in 2017 and 2019, and linked with administrative data. The primary outcome was pain disability. Results: In total, 6610 persons with back pain were considered for matching and we finally compared 200 persons treated in a medical rehabilitation program with 200 untreated subjects. Pain disability was reported more favorable in the control group without medical rehabilitation compared to the intervention group (difference = 4.2; 95% CI −0.8–9.2), as well as other secondary outcomes. Conclusions: At first glance, the findings suggest that medical rehabilitation was ineffective in improving health, pain and work ability among employed persons with back pain, but we found plausible explanations indicating that the estimated effects in favor of the untreated subjects are methodologically induced.IMPLICATIONS FOR REHABILITATION Propensity score matching can be used to assess the effects of multimodal interventions in persons with back pain in routine care. Inappropriate recruitment of controls may underestimate treatment effects. When using observational data and propensity score matching to analyze the effectiveness of medical rehabilitation, baseline survey should be conducted directly before the start of rehabilitation to identify comparable controls.