Impact of combining vancomycin with piperacillin/tazobactam or with meropenem on vancomycin-induced nephrotoxicity

Vancomycin (VAN) is a broad-spectrum antibiotic against Gram-positive cocci used empirically with other broad-spectrum antibiotics, such as piperacillin/tazobactam (TZP), cefepime, or meropenem (MEM). Conflicting literature on the rates of acute kidney injury (AKI) of VAN with TZP is reported, and studies on AKI rate with MEM are limited. This study aimed to evaluate AKI rates in patients receiving VAN with either TZP or MEM. This was a retrospective cohort study of patients received either VAN-TZP or VAN-MEM for >= 72 h. Patients with a baseline serum creatinine (SCr) of >= 1.5 mg/dL were excluded. The primary outcome was rate of AKI as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. SCr was recorded at baseline and 3-5 days post antibiotics initiation. 158 patients were included, 77 in the VAN-TZP group versus 81 in the VAN-MEM group. While the percentage of patients meeting AKI definition was numerically higher in the VAN-MEM group, the difference was not significant (10.4% vs. 21%; P = 0.07). As such, change in SCr was not significantly different between the two groups (- 7.4 vs. - 6.1%; P = 0.7). In-hospital mortality was higher in the VAN-MEM group (23.4% vs. 39.5%; P = 0.03) possibly because the majority of this group's patients were critically ill. This study showed that combining MEM with VAN did not offer the benefit of a lower rate of AKI compared with a combination with TZP. Therefore, patients with no risk factors for infections resistant to TZP can continue to receive TZP with VAN without risking AKI development.