The authors were interested in the extent that Lassa fever virus (LASV) diversity, host genetic and environmental factors may lead to differences in disease pathophysiology. They examined demographic, clinical and laboratory factors associated with mortality in Nigerian patients with Lassa fever by performing a retrospective, observational cohort study. Of 291 patients treated between 2011 and 2015, 98% had known outcomes (died or survived) and 2% were discharged against medical advice. Overall the case-fatality rate was 24%, with a 1·4-fold increase in mortality risk for every 10 years of age, reaching 39% for patients aged ≥50 years. Of 284 patients, 28% had acute kidney injury and 37% had CNS manifestations and therefore both of these were considered to be important complications of acute Lassa fever in Nigeria. Acute kidney injury was strongly associated with poor outcome (case-fatality rate 60%, odds ratio [OR] 15). Compared with patients without acute kidney injury, those with had a higher incidence of proteinuria (82%) and haematuria (76%), and higher mean serum potassium (4·63 mmol/L) and lower blood urea nitrogen to creatinine ratio (8·6), suggesting intrinsic renal damage. Normalisation of creatinine concentration was associated with recovery. Predictors of death included elevated serum creatinine (OR 1·3), aspartate aminotransferase (OR 1·5) and potassium (OR 3·6). Therefore there is evidence for intrinsic renal dysfunction in acute Lassa fever. Early recognition and treatment of acute kidney injury may significantly reduce mortality.
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