Prognostic factors associated with severe leptospirosis.

To determine the prognostic factors associated with severity and death of leptospirosis, the authors conducted a hospital based cross sectional study by collecting data of adult patients that were admitted to Phrae Hospital for leptospirosis from 1998 to 2001. The serology was confirmed with a microscopic agglutination test (MAT). The variables obtained from the history, examination, behavioral risks, investigations, and initial treatment especially the data of the first day of admission were examined for association with severity. Of 362 patients, 214 were classed as nonsevere patients, 81 were severe with complications (serum creatinine > or = 3 mg/dl and/or patients with respiratory failure) and 67 died. Multivariate logistic regression demonstrated that five factors were independently associated with severity: hemoptysis, platelet count (Plt) < 100,000/mm3, total bilirubin > 2.5 mg/dl, white blood cell count > 13,000/mm3 and hematocrit (Hct) < 30 per cent. Five factors associated with mortality are: respiratory failure (or respiratory rate; RR > 24/min), hemoptysis, oliguria, metabolic acidosis (or bicarbonate < 20 mmol/l) and thrombocytopenia (or Plt < 100,000/mm3). Identification of these factors might provide useful selection criteria for patients who need early admission or transfer to the intensive care unit.