BackgroundDiabetes self-management is a mainstay of diabetes care, but the implementation of self-management regimens into daily life is complex and often results in discouragement and distress. Modern approaches such as smartphone-based self-management applications are therefore needed to support people with diabetes. Since reimbursability would increase the availability of such digital applications to people with diabetes, we designed a study that meets all scientific and methodological requirements set by the German Digital Healthcare Act to allow reimbursement for a specific application (mySugr PRO). Here, we report the protocol of this study that aims at evaluating the efficacy of the digital self-management application with regard to patient-reported outcomes and medical benefits.Methods/designThis multicenter, open-label, randomized, parallel-group, controlled trial will evaluate the health care effects and medical benefits of mySugr PRO. A total of 466 people with diabetes will be randomly allocated (2:1 randomization) to the interventional group (n = 311) that will use the digital self-management application during the 12-week study period or the control group (n = 155; no usage of the application). Baseline and follow-up examinations will assess diabetes distress as the primary endpoint as well as empowerment, HbA1c, blood glucose data, self-management, general well-being, and treatment satisfaction as secondary endpoints. Statistical analyses will use an intention-to-treat procedure (using multiple imputation for missing values) as well as a per-protocol approach for sensitivity analysis.DiscussionTo the best of our knowledge, this study will be one of the largest diabetes-specific evaluations of a digital health application supporting people with diabetes in their diabetes self-management that follow the requirements of the German Digital Healthcare Act.Trial registrationGerman Clinical Trial Register DRKS00022923. Registered on 22 October 2020.