BackgroundChronic diseases are a significant and growing problem of our time. They impair the ability to work and increase the risk of early retirement. To support the return to work, rehabilitation services can be applied for in Germany. Currently, the application system for rehabilitation allows only a limited degree of individualisation of the treatment and is associated with a lack of multidisciplinary communication. To facilitate rehabilitation care planning, we developed a complex intervention. A digital, platform-based case management approach (intervention) will ensure multidisciplinary communication and the tailored selection of medical treatments and/or non-medical support measures. The overall objective is to assess the effectiveness of the intervention compared to treatment as usual (control condition). The German Federal Ministry of Labour and Social Affairs (BMAS) funds the RehaPro-SERVE study (grant number: 661R0053K1).MethodsThis is the protocol for an investigator-initiated, pragmatic, multicentre, randomised and controlled two-arm parallel-group superiority trial with embedded qualitative process evaluation. The study will be conducted in Hesse state, Germany. N = 59 primary care physicians will be recruited and tasked with the recruitment of six eligible patients each. Eligibility criteria: age 40–60; minimum of 4-week work disability due to musculoskeletal, oncologic or psychological conditions or the post-COVID-19 syndrome within the last 6 months; at high risk for early retirement. In total, n = 352 patients will be randomised with a 1:1 allocation to intervention or control group and stratified by primary care practice using permuted blocks. The primary outcome is the number of days of sick leave during a 12-month period after the assumed completion of treatments (t1 to t2). Secondary outcomes include the number of days of sick leave (self-report), work ability, and health-related quality of life, as well as data from the qualitative process evaluation.DiscussionThe results of the study will inform the design of future care services and provide valuable information on multidisciplinary case management in the context of rehabilitation care planning. The results of the qualitative process evaluation will further contribute to the understanding of facilitating and hindering factors.Trial registrationDRKS-German Clinical Trials Register, DRKS0 00242 07. Registered on 22 March 2021.