Effect of concomitant vancomycin and piperacillin-tazobactam on frequency of acute kidney injury in pediatric patients.

PURPOSE Results of a study of rates of acute kidney injury (AKI) in pediatric patients treated with vancomycin plus piperacillin-tazobactam or vancomycin plus alternative antipseudomonal β-lactams (APBLs) are reported. METHODS A retrospective, single-center cohort study was performed. Pediatric patients were included in the study cohort if they received combination therapy for at least 48 hours, had documented baseline and follow-up serum creatinine levels, and had a documented serum vancomycin trough concentration. The primary outcome was the frequency of AKI, defined as a 50% or greater increase in serum creatinine concentration from baseline or an increase of at least 0.5 mg/dL from baseline. The secondary outcome was time to AKI onset. RESULTS A total of 474 patients were included. Among 100 patients who received vancomycin plus piperacillin-tazobactam, the rate of AKI was higher than the rate in the group treated with vancomycin plus alternative APBLs (27% versus 7%, p < 0.0001). The median time to AKI onset was shorter in the piperacillin-tazobactam group versus the alternative APBL group (3.8 versus 7.9 days, p = 0.0065). Patients who were administered piperacillin-tazobactam were almost 6 times as likely to develop AKI (odds ratio [OR], 5.955; 95% confidence interval [CI], 2.774-12.784), and patients who had a maximum vancomycin trough concentration greater than 20 mg/L were 7.5 times as likely to develop AKI (OR, 7.552; 95% CI, 3.625-15.734). CONCLUSION Pediatric patients treated with concomitant vancomycin and piperacillin-tazobactam had a higher rate of AKI, with faster AKI onset, than those who received vancomycin in combination with other APBLs.