Predictors of Lethality in Severe Leptospirosis in Urban Brazil

Abstract. To ascertain prognostic factors associated with fatal outcomes in severe leptospirosis, a retrospective case-control study was done using population-based surveillance data. Centralized death certificate reporting of lep-tospirosis mortality was combined with details of patients ’ hospitalizations, which were obtained from hospitals repre-senting all sectors of São Paulo city. Among identified leptospirosis cases, 89 lethal cases and 281 survivor cases were analyzed. Predictors of death included age> 40 years, development of oliguria, platelet count < 70,000/L, creatinine> 3 mg/dL, and pulmonary involvement. The latter was the strongest risk factor with an estimated odds ratio of 6.0 (95% confidence interval: 3.0–12.0). Serologic findings with highest titer against Leptospira interrogans serovar Copenhageni did not show significant differences between survivors and non-survivors. Lung involvement was an important predictor of death in leptospirosis in São Paulo, of relevance in leptospirosis-endemic regions where this complication is common