Abstract: Diabetes mellitus is associated with risk factors and diseases such as obesity. At the same time, cardiovascular diseases in particular are a frequent consequence of diabetes. To date, there is a lack of nationwide results with data from persons with statutory health insurance that simultaneously represent the prevalence of diabetes and the diseases that frequently occur together with it. This study calculates the documented prevalence with respect to diabetes in 2019 based on all outpatient contract medical billing data. In addition, the prevalence of obesity, hypertension, coronary heart disease, heart failure, stroke and depression in persons with and without diabetes is calculated and the prevalence ratio (PR) is determined as a quotient. A case-control design was chosen for this purpose, which assigns to each diabetes case a comparable person without diabetes in terms of age, region, and sex as a control. All investigated diseases show a PR of greater than 1 in persons with diabetes in all age groups and thus a higher prevalence compared to persons without diabetes. The highest PR across all age groups is found for obesity in women (3.8) and men (3.7). In a comparison over time, the nationwide billing prevalence of diabetes has stagnated. With the exception of depression, documented prevalences of comorbidities agree well with prevalences from population-based screening surveys.