Supplementary Material for: Healthcare Burden and Costs Associated with Urinary Tract Infections in Type 2 Diabetes Mellitus Patients: An Analysis Based on a Large Sample of 456,586 German Patients

Objectives: We examined the real-world treatment of urinary tract infections (UTIs) in a type 2 diabetes mellitus (T2DM) population, evaluated UTI-related healthcare resource use and direct treatment costs, and assessed factors that may predict UTI-related costs. Methods: We analyzed an anonymized dataset from a regional German healthcare fund (2010-2012). UTI-associated resource use was described by the number of UTI-associated outpatient visits, the number and length of UTI-related acute hospital visits, and the number of UTI-related antibiotics prescriptions. UTI-related direct treatment costs were studied both based on these resource use numbers and, additionally, based on a comparison of all-cause annual healthcare costs of T2DM-patients who were or were not affected by a UTI. To identify factors that might predict direct treatment costs related to UTI treatment, we conducted generalized linear regression model analyses (based on gamma distribution) using sociodemographic and clinical characteristics of observed patients as available in the database as independent variables. Results: A total of 456,586 T2DM-patients were included with a mean age of 73.8, a percentage of 56.3 female patients, and a mean Charlson comorbidity index of 7.3. In our database, we observed 48,337 UTI events. The direct mean resource-based costs were €315.90 per UTI event. Older age, higher comorbidity status, at least one previous non-UTI infection, and poorer renal function were associated with higher costs, while female gender and at least one previous UTI event were associated with lower costs. In the all-cause cost analysis, healthcare costs per patient year were €3,916 higher in the UTI group than in the non-UTI group. Conclusion: Our study confirms that UTI is a common complication in patients with T2DM. Patients with T2DM who have had previous infections, who are older, and who are male, as well as patients who have more comorbidities or severe renal insufficiency, face above-average UTI treatment costs. These patient groups, therefore, should receive special attention in the real-world treatment of T2DM, which should include a regular screening of UTI risk.