The growing burden of infectious arthritis in Germany: a nationwide analysis of epidemiology, mortality, and contemporary inpatient care

Abstract Purpose Infectious arthritis is a destructive joint infection associated with substantial morbidity and mortality. We characterised long-term changes in its inpatient epidemiology and outcomes in Germany and complemented these trends with contemporary nationwide inpatient data. Methods Nationwide hospital discharge data for pyogenic arthritis (ICD-10-GM M00) were obtained from the German Federal Health Monitoring database for 2000–2023. Hospitalisations, age-standardised rates, demographic patterns, pathogen-specific diagnostic codes, in-hospital mortality, and length of stay were analysed. Nationwide Diagnosis-Related Group data from 2019 to 2024 characterised contemporary inpatient and procedural patterns. Temporal trends were assessed by log-linear regression. Results Annual hospitalisations increased from 6,088 in 2000 to 21,051 in 2023 (annual percentage change [APC] 5.28%, 95% CI 4.54–6.03; P < 0.001), while the age-standardised hospitalisation rate rose from 8 to 25 per 100,000 population (APC 4.65%, 95% CI 3.93–5.38; P < 0.001). In-hospital deaths increased from 85 to 734 (APC 9.37%, 95% CI 8.52–10.20; P < 0.001), and crude in-hospital mortality increased from 1.40% to 3.49% (APC 3.88%, 95% CI 3.20–4.56; P < 0.001). InEK case volume further increased from 15,338 in 2019 to 22,446 in 2024. Conclusion Infectious arthritis represents a growing inpatient burden in Germany, with increases persisting after age standardisation and accompanied by rising crude in-hospital mortality. The findings support continued surveillance and studies integrating administrative, clinical, and microbiological data.