The Impact of Acute Kidney Injury on the Risk of Mortality and Health Care Utilization Among Patients Treated With Polymyxins for Severe Gram-Negative Infections

Background. With the rise of antibiotic resistance, polymyxin use has re-emerged but with a concern of renal toxicity. This study aims to assess mortality, length of stay, and total hospitalization cost associated with acute kidney injury (AKI) among recipients of intravenous (IV) sodium colistimethate (CMS) or IV polymyxin B (PMB). Methods. We conducted a retrospective database analysis using the Premier database from January 1, 2012, through September 30, 2015. Adults >= 18 years of age who were admitted for inpatient treatment with >= 3 consecutive days of CMS or PMB were included. Generalized linear models compared patients who developed AKI with those who did not. Models were adjusted for patient and clinical characteristics. Results. A total of 4886 patients were included; 4103 patients received CMS, and 783 received PMB. In the multivariable analyses, the presence of AKI was associated with higher in-hospital mortality in both the CMS cohort (adjusted odds ratio [aOR], 2.3; 95% confidence interval [CI], 1.9-2.7; P<.001) and the PMB cohort (aOR, 2.7; 95% CI, 1.8-4.2; P <.001). In both cohorts, patients who developed AKI experienced longer hospital stays (9.7 days and 11.6 days in the CMS and PMB cohorts, respectively; P <.001). The mean total hospitalization costs for patients who developed AKI were $47 820 higher (95% CI, S34 918-$60 722) in the CMS cohort and $35 244 higher (95% CI, $17 561 $52 928) in the PMB cohort. Conclusions. The clinical and economic burden of AKI in the context of polymyxin use is substantial. The use of effective antibiotics with limited toxicity should remain a priority.