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

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.

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.

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.

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.