Prognostic factors of death in leptospirosis: a prospective cohort study in Khon Kaen, Thailand.

OBJECTIVES: To determine the prognostic factors of death in leptospirosis. METHODS: A prospective cohort study was conducted. One hundred and twenty one patients with clinically compatible leptospirosis, serologically confirmed, were recruited in this study. Clinical presentations and biochemical parameters on admission were selected as input variables for survival analysis. Multivariable Cox regression model was used to identify the prognostic factors of death. RESULTS: Most patients were male (94.2%), with the mean +/-SD age of 38+/-13.4 years; 77.4% of them were farmers. Among the 121 patients, 1206 patient-days were observed. Seventeen patients died. Overall mortality rate was 1.4 per 100 patient-days (95% confidence interval [CI]: 0.9-2.3). The causes of death included: a) pulmonary hemorrhage in eight (47.1%) patients; b) complicated acute renal failure in three (17.6%) patients; c) multiple organ failure in three (17.6%) patients; d) acute respiratory distress syndrome in two (11.8%) patients, and e) irreversible shock in one (5.9%) patient. Four independent risk factors associated with the mortality were identified, including hypotension (relative risk [RR], 10.3; 95% CI, 1.3-83.2; P<0.05); oliguria (RR, 8.8; 95% CI, 2.4-31.8; P<0.01); hyperkalemia (RR, 5.9; 95% CI, 1.7-21; P<0.01), and presence of pulmonary rales (RR, 5.2; 95% CI, 1.4-19.9; P<0.05). CONCLUSION: The presence of oliguria, hyperkalemia, pulmonary rales, or hypotension on admission in patients with leptospirosis indicated high risk of death. Intensive care and early intervention should be provided for patients who present with these risk factors.