Changing patterns in leptospirosis: a three-decade study in Brazil.

BACKGROUND: This study was conducted to investigate changes in the clinical pattern of leptospirosis over time, analyzing its clinical and laboratory presentations in a metropolitan city of Brazil. METHOD: This was a retrospective study including all patients with leptospirosis admitted to tertiary care hospitals in Fortaleza in the northeast of Brazil, between 1985 and 2015. Patients were divided into three groups according to the year of hospital admission: group I for the years 1985-1995, group II for 1996-2005, and group III for 2006-2015. Demographic, clinical, and laboratory data were compared between the groups. RESULTS: A total of 507 patients were included. Their mean age was 37.3±15.9years and 82.4% were male. The mean time between symptom onset and admission was 7±4 days. There was a linear decrease in the levels of serum urea (190.1±92.7, 135±79.5, and 95.6±73.3mg/dl, respectively, p <0.0001) and creatinine (5.8±2.9, 3.8±2.6, and 3.0±2.5mg/dl, respectively, p <0.0001) in each decade, while levels of hemoglobin (10.31±1.9, 10.8±2.0, and 11.5±2.1g/dl, respectively, p <0.0001) and platelets (57.900±52.650, 80.130±68.836, and 107.101±99.699×109/l, respectively, p<0.0001) increased. There was a tendency towards a linear decrease in mortality (22%, 14%, and 11.6%, respectively, p=0.060). CONCLUSIONS: Leptospirosis showed significant changes over time in this region. The main changes point to a decrease in disease severity and complications, such as acute kidney injury. Mortality has decreased, being close to 11%.