Clinical and laboratory parameters associated with acute kidney injury in patients with snakebite envenomation: a prospective observational study from Myanmar

Background: Snakebite-related acute kidney injury (AKI) is a common community-acquired AKI in tropical countries leading to death and disability. The aims of this study were to (1) determine the occurrence of snakebite-related AKI, (2) assess factors at presentation that are associated with snakebite-related AKI, and (3) determine the outcomes of patients with snakebite-related AKI. Methods: We conducted a prospective observational study of patients with snake envenomation at the three academic tertiary care hospitals in Yangon, Myanmar between March 2015 and June 2016. Patient data including baseline characteristics, clinical and laboratory findings, hospital management, and outcomes were recorded in a case report form. A stepwise multivariate logistic regression analysis using a backward selection method determined independent factors significantly associated with AKI. Results: AKI was observed in 140 patients (54.3%), the majority of whom were AKI stage III (110 patients, 78.6%). AKI occurred at presentation and developed during hospitalization in 88 (62.9%) and 52 patients (37.1%), respectively. Twenty-seven patients died (19.3%), and 69 patients (49.3%) required dialysis. On multivariate logistic regression analysis, (1) snakebites from the Viperidae family (odds ratio [OR]: 9.65, 95% confidence interval [CI]: 2.42-38.44; p = 0.001), (2) WBC > 10 x 10(3) cells/mu L (OR: 3.55, 95% CI: 1.35-9.34; p = 0.010), (3) overt disseminated intravascular coagulation (OR: 2.23, 95% CI: 1.02-4.89; p = 0.045), (4) serum creatine kinase > 500 IU/mu L (OR: 4.06, 95% CI: 1.71-9.63; p = 0.001), (5) serum sodium < 135 mmol/L (OR: 4.37, 95% CI: 2.04-9.38; p < 0.001), (6) presence of microscopic hematuria (OR: 3.60, 95% CI: 1.45-8.91; p = 0.006), and (7) duration from snakebite to receiving antivenom >= 2 h (OR: 3.73, 95% CI: 1.48-9.37; p = 0.005) were independently associated with AKI. Patients bitten by Viperidae with normal renal function who had serum sodium < 135 mmol/L had a significantly higher urine sodium-to-creatinine ratio than those with serum sodium >= 135 mmol/L (p < 0.001). Conclusions: Identifying factors associated with snakebite-related AKI might help clinicians to be aware of snakebite patients who are at risk of AKI, particularly patients who demonstrate renal tubular dysfunction after Viperidae bites.