Hyponatremia and risk factors for death in human visceral leishmaniasis: new insights from a cross-sectional study in Brazil

BACKGROUND Visceral leishmaniasis (VL) is an important and potentially fatal neglected tropical disease. The aim of this study was to investigate hyponatremia and risk factors for death among VL patients. METHODS This is a cross-sectional study with VL patients admitted to a tertiary hospital in Northeast Brazil, from 2002 to 2009. Patients were divided into two groups: non-survivors and survivors. Hyponatremia was defined as serum sodium < 135 mEq/L. A logistic regression model was done to investigate risk factors for death. RESULTS A total of 285 VL patients were included, with mean age 37 ± 15 years, and 74% were males. Thirty-four patients died (11.9%). Non-survivors had a significantly higher prevalence of dyspnea (38.2 vs. 16.7%, p = 0.003), pulmonary crackles (11.8 vs. 4.0%, p = 0.049), dehydration (23.5 vs. 10.8%, p = 0.033), oliguria (8.8 vs. 0.8%, p = 0.001) and jaundice (47.1 vs. 14.3%, p < 0.001). They also presented higher prevalence of hyponatremia (41.9 vs. 24.1%, p = 0.035), thrombocytopenia (91.2 vs. 65.3%, p = 0.002) and severe hypoalbuminemia (78.3 vs. 35.3%, p < 0.001). In multivariate analysis, moderate/severe hyponatremia (OR = 2.278, 95% CI = 1.046-4.962), thrombocytopenia (OR = 5.482, 95% CI = 1.629-18.443), jaundice (OR = 5.133, 95% CI = 1.793-14.696) and severe hypoalbuminemia (OR = 6.479, 95% CI = 2.124-19.766) were predictors of death. CONCLUSION Higher prevalence of dehydration, oliguria, pulmonary symptoms and liver involvement was found in non-survivors VL patients. Hypoalbuminemia and hyponatremia were frequent and significantly associated with mortality.