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

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 REHABILITATIONPropensity 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.