Polymyxin B-Associated Acute Kidney Injury: Risk Factors and Short-Term Outcomes in a Single-Center Retrospective Cohort

Introduction. Polymyxin B (PMB) and other antibiotics in the polymyxin group are known to be nephrotoxic. In recent years, due to the increasing prevalence of antibiotic resistance, they have become a frequent treatment option for infections caused by multidrug-resistant Gram-negative bacteria. Our study aims to comprehensively examine the nephrotoxic effects and clinical characteristics of PMB in patients receiving treatment without dose reduction. Methods. This study included 176 patients, who were divided into two groups based on the presence or absence of acute kidney injury (AKI). The groups were analyzed for nephrotoxicity, associated risk factors, mortality, and other clinical characteristics. Results. Gender, pathogen, site of infection, comorbidities, additional nephrotoxic agents, duration of antibiotic use, and mechanical ventilation status were not identified as risk factors for AKI development. However, advanced age was found to be associated with nephrotoxicity (OR = 1.024, 95% CI 1.001–1.047; p = 0.037). Additionally, the mortality rate was higher in the AKI group (p = 0.001), although no significant difference was observed in the survival analysis (p = 0.189). Conclusions. PMB is commonly used in critically ill patients, and PMB-associated AKI tends to develop early during treatment. While most clinical characteristics were not independently associated with AKI, advanced age was identified as a significant risk factor. Therefore, close monitoring of renal function is recommended throughout PMB therapy.