Comparison of Rates of Acute Kidney Injury with Vancomycin/Piperacillin-Tazobactam vs. Vancomycin/Meropenem Combination Therapy

BACKGROUND: Vancomycin is historically correlated with renal toxicity, especially in conjunction with other nephrotoxins. Recent reports have identified nephrotoxicity associated with vancomycin in conjunction with β-lactam antibiotic therapy, reporting increased rates of acute kidney injury (AKI) with vancomycin/piperacillin-tazobactam (VPT) therapy as compared with vancomycin monotherapy. Similarly, increased rates of AKI have been reported with VPT as compared with vancomycin/cefepime. Little data exists comparing VPT to the combination of vancomycin/meropenem (VM). The purpose of this study was to compare the incidence of nephrotoxicity between these two antibiotic combinations. METHODS: A single-center cohort study was performed at a large tertiary care community hospital utilizing retrospective review of electronic medical records. Adult in-patients treated from June to October of 2015 were included. Evaluable patients received at least 48 hours of either VPT or VM combination therapy and were followed for up to 10 days of combination therapy. Data collection included patient demographics, AKI risk factors, days of antibiotic therapy, and serum creatinine. The primary endpoint was incidence of AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included time to AKI and incidence of new dialysis treatment. RESULTS: Of 564 patients screened, a total of 202 patients met inclusion criteria, with 101 patients in each combination therapy group. Baseline serum creatinine and estimated creatinine clearance were not different between groups. The incidence of AKI was higher in the VPT group as compared with the VM group (17.82% vs. 4.95%, respectively, P = 0.004). Time to AKI onset was longer in the VPT group compared with the VM group (3.2 days vs. 1.4 days, P = 0.045). Patients in the VM group had a higher incidence of ICU admissions (56.4% vs. 40.6%, P = 0.024) and mean arterial pressure (MAP) less than 65mmHg (60.4% vs. 44.6%, P = 0.029). No patients in either group required new dialysis therapy. CONCLUSION: Despite a greater incidence of AKI risk factors in the VM group, VPT therapy was associated with an increased risk of AKI as compared with VM therapy. Prospective studies are needed to further evaluate this finding. DISCLOSURES: All authors: No reported disclosures.