Risk factors and outcomes stratified by severity of acute kidney injury in malaria.

Severe acute kidney injury (AKI) is known to have prognostic value for in-hospital outcomes in malaria. However, little is known about the association of AKI of lesser severity with malarial risk factors and outcomes--and such a gap is becoming increasingly relevant with the upsurge in the incidence of AKI due to Plasmodium falciparum malaria and Plasmodium vivax malaria over the last decade. We aimed to identify risk factors of AKI in malaria and assessed in-hospital outcomes stratified by severity of AKI. We performed an observational study of 1,191 hospitalized malaria patients enrolled between 2007 and 2011 in a tertiary care academic center in India. Patients were categorized based on peak serum creatinine into one of three groups: no AKI (<1.6 mg/dL), mild AKI (1.6-3.0 mg/dL), and severe AKI (>3 mg/dL). Plasmodium vivax was the predominant species (61.41%), followed by Plasmodium falciparum (36.41%) and mixed infections with both the species (2.18%). Mild and severe AKI were detected in 12% and 5.6% of patients, respectively. Mild AKI due to Plasmodium vivax (49%) and Plasmodium falciparum (48.5%) was distributed relatively equally within the sample population; however, cases of severe AKI due to Plasmodium falciparum (80%) and Plasmodium vivax (13%) was significantly different (P<0.001). On history and physical examination, risk factors for AKI were age, absence of fever, higher heart rate, lower diastolic blood pressure, icterus, and hepatomegaly. The only laboratory parameter associated with risk of AKI on multivariate analysis was direct bilirubin. Patients with mild and severe AKI had greater organ complications, supportive requirements, longer duration of hospital stay and in-hospital mortality in a dose-dependent relationship, than patients with no AKI. Mild AKI is associated with significant (P<0.05) morbidity compared to no AKI, and future studies should assess strategies for early diagnosis of AKI and prevent AKI progression.