Pre-post changes in main outcomes of medical rehabilitation in Germany: protocol of a systematic review and meta-analysis of individual participant and aggregated data.

Introduction: Multidisciplinary, complex rehabilitation interventions are an important part of the treatment of chronic diseases. However, little is known about the effectiveness of routine rehabilitation interventions within the German healthcare system. Due to the nature of the social insurance system in Germany, randomised controlled trials examining the effects of rehabilitation interventions are challenging to implement and scarcely accessible.