Background
Septic arthritis (SA) presents a complex clinical challenge, often resulting in significant morbidity and mortality. This study aimed to (1) assess overall mortality rates and (2) identify potential factors contributing to increased mortality risk in patients with SA.

Methods
This retrospective study on SA patients treated at a German university hospital between January 1, 2011, and December 31, 2021. Patients were identified using International Classification of Diseases (ICD)-10 codes for septic arthritis, specifically “M00.-”. The study evaluated mortality rates and analyzed comorbidities, pathogens, and other potential risk factors. Kaplan–Meier survival curves and odds ratios (OR) were calculated to assess mortality risk.

Results
In a cohort of 192 patients diagnosed with SA, 64 patients (33.3%) died during a mean follow-up period of 54.4 ± 42 months. The overall mortality rate was 17.5% at one year, 19.9% at two years, and 28.3% at five years. Patients aged 65 years or older, as well as those with arterial hypertension, congestive heart failure, chronic renal disease, chronic liver disease, malignancy, steroid use and immunosuppression showed significantly higher mortality rates (p < 0.05). Chronic renal disease (OR = 2.80), malignancy (OR = 3.40), and chronic heart failure (OR = 2.62) were identified as significant notably risk factors for mortality.

Conclusion
This study highlights a notably high mortality rate among vulnerable patients with SA, particularly those with pre-existing comorbidities. Recognizing and addressing these risk factors early could improve patient outcomes. These results unterscore the need for close monitoring of SA patients, particularly those with chronic organ conditions, and timely intervention for sepsis to reduce mortality risk.