Predictors of in-hospital mortality in severe leptospirosis: a retrospective cohort study (São Paulo, 2017–2025)

PURPOSE: Although advances in intensive care have improved survival of patients with severe leptospirosis, it remains with high mortality. We aimed to identify factors associated with in-hospital mortality among patients with severe leptospirosis admitted to a tertiary intensive care unit. METHODS: We conducted a retrospective cohort study of adults with leptospirosis admitted to the ICU of a tertiary referral hospital in Brazil, between January 1, 2017, and March 3, 2025. Demographic, clinical, laboratory, and intensive care support variables were collected. The primary outcome was in-hospital mortality. Multivariable logistic regression models were used to identify independent predictors of death. RESULTS: Forty-four patients were included; median age was 42 years, and 95.5% were male. In-hospital mortality was 20.5% (9/44). Severe multiorgan dysfunction was common; 56.8% of patients required renal replacement therapy and invasive mechanical ventilation in 43.2%. In the clinical multivariable model, alveolar hemorrhage (aOR 7.91, 95% CI 1.07-58.61) and arrhythmia (aOR 13.82, 95% CI 2.06-92.64) were independently associated with death. In the laboratory-based model, urea > 180 mg/dL (aOR 9.01, 95% CI 1.36-59.65) and platelet count < 45 × 10³/mm³ (aOR 14.07, 95% CI 1.40-141.88) were independently associated with mortality. CONCLUSION: In this contemporary ICU cohort, mortality in severe leptospirosis was primarily driven by respiratory and cardiac complications rather than isolated renal dysfunction. Although renal failure remained a marker of severity, its prognostic impact appeared attenuated by timely renal replacement therapy.