A retrospective cohort study assessing acute kidney injury and renal recovery among septic patients empirically treated with vancomycin piperacillin–tazobactam versus vancomycin cefepime

Vancomycin plus piperacillin–tazobactam (VPT) is a commonly used antimicrobial regimen for septic patients. VPT is more nephrotoxic than other regimens such as vancomycin plus cefepime (VC) when given over several days. This risk of nephrotoxicity is less clear when VPT is given for initial empiric therapy in sepsis and de-escalated quickly based on evolving clinical information. The objective of this study was to assess nephrotoxicity among septic patients empirically treated with either VPT or VC at initial clinical presentation. We conducted a retrospective study of septic patients who received VPT or VC within 12 h of presentation to the emergency department. The primary outcomes were acute kidney injury (AKI) and renal recovery 72 h after presentation. For the total of 418 patients, 306 received VPT and 112 received VC. Rates of AKI at 72 h were 15.2% for VPT patients and 11.0% for VC patients [p = 0.44]. Among patients with AKI at presentation, 16.3% of VPT patients had AKI at 72 h compared to 8.9% of VC patients [p = 0.19]. Among those without AKI at presentation, 14.2% VPT patients and 16.7% VC patients had AKI at 72 h [p = 0.71]. Renal recovery rates for patients with AKI at presentation were 42.3% for VPT patients versus 40.3% for VC patients [p = 0.78]. In-hospital renal replacement therapy occurred in 6.2% VPT patients and 0.9% VC patients [p = 0.024]. Therefore, initial empiric therapy with VPT in sepsis may not confer increased risk of AKI when de-escalated appropriately.