2292. Incidence of Acute Kidney Injury Associated with Duration of Vancomycin and Piperacillin/tazobactam Combination Therapy

BACKGROUND: Empiric antibiotic therapy for serious and healthcare-acquired infections often requires coverage for resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. These regimens commonly consist of vancomycin plus an antipseudomonal β-lactam. Recent studies have reported increased acute kidney injury (AKI) risk associated with concomitant vancomycin and piperacillin/tazobactam therapy compared with each agent alone. The objective of this study was to determine whether vancomycin with piperacillin/tazobactam had an increased AKI incidence compared with vancomycin plus cefepime or meropenem. Furthermore, data were analyzed to determine whether a specific duration was associated with an increased AKI incidence. METHODS: A retrospective cohort study was conducted analyzing patients who received vancomycin in combination with piperacillin/tazobactam (V+PT), cefepime (V+C), or meropenem (V+M) between January 1, 2018 through June 30, 2018. Adult patients with normal baseline renal function and receipt of at least 48 hours of combination therapy, with the two antibiotics initiated within 24 hours of one another, were included. AKI events, evaluated using the Acute Kidney Injury Network (AKIN) criteria, during antibiotic therapy and up to 72 hours after antibiotic discontinuation were recorded. This data were used to calculate the AKI incidence with each regimen and AKI incidence associated with each day of therapy. RESULTS: A total of 181 patients were included in the study. The incidence of AKI in the V+PT group was 22.8% vs. 5.6% and 16.7% in the V+C and V+M groups, respectively (P = 0.237). Median duration of therapy when AKI occurred was 3 days for V+PT, 4 days for V+C, and 2 days for V+M (P = 0.015). Patients in the V+M group received more nephrotoxic agents compared with V+PT and V+C (P = 0.004). Statistical analysis did not find a specific day of V+PT therapy predictive of AKI. However, a time to event analysis demonstrated a steady increase in AKI risk with V+PT from day 2 through 6. CONCLUSION: Although not statistically significant, V+PT therapy was associated with a higher incidence of AKI compared with V+C or V+M. Future studies are needed to further assess the impact of duration of therapy on AKI incidence. DISCLOSURES: All authors: No reported disclosures.