Epidemiology and Course of Clostridioides difficile Infections in Germany: Retrospective Analysis of German Health Claims Data.

Introduction: Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated infectious diarrhea, with recurrence rates of 15-20% after standard treatment and ≥ 30% after a second relapse. In Germany, reliable epidemiological data remain limited.

Methods: A retrospective claims data analysis of the period 2017-2022 was performed using the German Analysis Database for Evaluation and Health Services Research (DADB), which covers 4.1 million insured individuals. Incident CDI cases, recurrent cases, and mortality were assessed and stratified by diagnosis setting. A propensity-score-matched control group without CDI adjusted for age, sex, and comorbidities was created. Cox proportional hazards models were used to determine mortality risk factors.

Results: CDI incidence decreased from 119 to 66 per 100,000 (2017-2022). First-recurrence rate declined from 15% to 11% and second-recurrence rate from 20% to 15%. Of all recurrences, 43% were managed in the outpatient setting. In 2022, severe CDI accounted for 38% of extrapolated statutory health insurance (SHI) cases. Metronidazole use in outpatients decreased from 79% to 53% for incident cases, while vancomycin prescriptions increased from 18% to 39%. In 2022, 72% of first CDI recurrences were treated with vancomycin, 20% with metronidazole, and 2% with fidaxomicin. Despite guideline recommendations, only 8% of patients with a second recurrence received fidaxomicin. In 2021, the 30-day mortality rate for secondary inpatient CDI cases was 20%, compared with 8% for primary inpatient cases and 4% for outpatient cases. Corresponding 1-year mortality rates were 44%, 32%, and 16%. In patients with CDI, 1-year mortality was 1.9 to 2.1 times higher than in controls (p < 0.001), with advanced age (≥ 65 years) being the strongest predictor (hazard ratio [HR] 12.21; 95% confidence interval [CI] 10.91-13.67).

Conclusions: Despite declining incidence and recurrence rates, CDI remains a major health burden in Germany, especially for older adults. High severity, limited adherence to treatment guidelines, and excess mortality underscore the need for targeted prevention, individualized therapy, and improved guideline implementation.