Incidence of Acute Kidney Injury Among Intensive Care Unit Patients Receiving Vancomycin in Combination with Cefepime or Piperacillin–Tazobactam

BACKGROUND: Combination therapy with piperacillin-tazobactam (TZP) and vancomycin (VAN) has been associated with increased AKI incidence when compared with cefepime (FEP) and VAN. However, this was not seen in critically ill patients, we hypothesized that critically ill patients receiving TZP+VAN would have a higher AKI incidence compared with those receiving FEP+VAN. METHODS: Clinical and demographic data were collected from the University of Kentucky Center for Clinical and Translational Science Enterprise Data Trust. Adult patients were included if they received TZP+VAN or FEP+VAN for ≥ 48 hours in the ICU. Patients were excluded for initial CrCl < 30 mL/minute, receipt of other β-lactam agents, past medical history of CKD. AKI cases were identified via the RIFLE criteria. Variables were analyzed via appropriate statistical tests. Patients were propensity score matched on a 1:1 basis on variables that were significantly different at baseline or associated with AKI. RESULTS: Overall, 1871 patients were included in this study, with 1205 receiving TZP+VAN and 666 receiving FEP+VAN. At baseline, TZP+VAN patients were older (56 [45–65] vs. 52 [37–63] years; P < 0.00001). Vasopressor exposure was more common in the FEP+VAN group (32.6% vs. 27.0%, P = 0.01). AKI incidence was higher in the TZP+VAN group (31.8% vs. 18.0%, P < 0.00001). Following matching, 1282 patients were included with 641 patients in each group. The cohorts were similar in baseline AKI risk factors, except hypertension (TZP+VAN 59.4% vs. 53.4%, P = 0.03), and loop diuretic exposure (53.4% vs. 46.7%, P = 0.02). AKI was significantly more common in TZP+VAN patients (34.2% vs. 17.8%, P < 0.00001) and after controlling for remaining confounders, TZP+VAN had 2.51 times the odds of experiencing AKI than those in the FEP+VAN (95% CI 1.9–3.34). Other factors associated with increased odds of AKI included: increasing severity of illness, higher baseline renal function, exposure to calcineurin inhibitors, vasopressors, and loop diuretics, diagnosis of heart failure, and duration of antimicrobial therapy > 7 days. CONCLUSION: TZP+VAN therapy is associated with significant increases in AKI in critically ill patients compared with those who received FEP+VAN independent of other AKI risk factors. DISCLOSURES: All authors: No reported disclosures.