Evaluation of the Risk for Acute Kidney Injury in Adult Cystic Fibrosis Patients Receiving Concomitant Vancomycin and Tobramycin

Background The risk for acute kidney injury (AKI) has been associated with both tobramycin and vancomycin. Objective To determine whether the rate of drug therapy-related nephrotoxicity is greater in Cystic Fibrosis (CF) patients receiving concomitant vancomycin and tobramycin than patients receiving either agent alone. Methods Adult CF patients admitted for acute pulmonary exacerbation (APE) over a seven-year period (2008-2014), who received at least 72 hours of intravenous vancomycin, tobramycin or a combination of the two agents were evaluated for AKI. AKI was defined as a 1.5-fold increase in serum creatinine per RIFLE criteria. One hundred seventy-four hospital encounters from 72 unique patients were assessed in this single-center, cross-sectional study. Results AKI outcomes were not statistically different. AKI rates were 19% for vancomycin, 8.7% for tobramycin, and 19.7% for combination cohorts (p = 0.16). Conclusion Our data suggest there is no significant difference in AKI risk when vancomycin and tobramycin combination therapy is used.