Colistin-associated acute kidney injury in intensive care unit patients: Significance of other confounding factors

Abstract

Colistin is a valuable antibiotic for controlling gram-negative pathogens, but the associated nephrotoxicity is an important side effect which limits its use. This study aimed to evaluate the incidence of colistin-associated nephrotoxicity and the role of other confounding factors in the incidence of acute kidney injury (AKI) in critically ill patients. In this prospective cohort study, all patients over 18 years with a positive culture for Acinetobacter baumannii who admitted to ICUs from March 2017 to February 2019 were enrolled. They were divided into two groups; the study group received colistin but the control group consisted of patients who were positive for Acinetobacter culture but due to unavailability of the drug, colistin was not prescribed. Demographic data and clinical characteristics were recorded in a designed questionnaire. The primary outcome was the occurrence of renal failure based on the KDIGO criteria. In total 115 patients were studied, 75 (65.2%) cases and 40 (39.8%) controls. The incidence rate of AKI in the colistin and control groups was 48 and 17.5%, respectively indicating a statistically significant difference (P=0.033). AKI was established on average in the first 6 days of colistin administration. There is no significant difference between the daily and total dose of colistin consumption in patients with AKI and without AKI in the colistin group. After adjusting the confounding variables such as the age of patients, use of simultaneous and potentially nephrotoxic drugs and hypotensive episodes we get an Odds Ratio of 2.48 with a 95% Confidence interval of 0.97 to 6.36 and a P-value of 0.059. Colistin is an antibiotic with potential capability for AKI development in ICU patients; however, its incidence in critically ill patients is associated with factors other than colistin as well.