Abstract

Concomitant therapy with vancomycin (VAN) and piperacillin–tazobactam (PTZ) has been associated with acute kidney injury (AKI). Diabetic patients may be more susceptible to AKI due to various factors. In an observational, retrospective, cohort study of adults treated for diabetic foot infections (DFIs), rates of AKI were compared between groups receiving VAN+PTZ versus VAN+cefepime (CFP). Among 356 patients screened for inclusion, 210 were analyzed. Forty-nine of 140 patients (35%) in the VAN+PTZ group and 5 of 70 patients (7%) in the VAN+CFP group developed AKI according to the Acute Kidney Injury Network criteria (OR 7.00 (95% CI 2.64 to 18.53), p<0.001). After adjusting for baseline differences, VAN+PTZ was an independent predictor of AKI (OR 6.21 (95% CI 2.30 to 16.72), p<0.001). Time to AKI was 102.1 hours (IQR 47–152.7) in the VAN+PTZ group versus 78.3 hours (IQR 39.8–100.6) in the VAN+CFP group (p>0.999). Median length of stay was significantly higher in the VAN+PTZ group at 11.9 days (IQR 7.9–17.8) versus 7.8 days (IQR 4.9–12.1) in the VAN+CFP group (p<0.001). VAN+PTZ was also associated with higher total hospital charges at US$99,742.83 (IQR US$69,342.50–US$165,549.59) compared with US$74,260.25 (IQR US$48,446.88–US$107,396.99) in the VAN+CFP arm (p<0.001). In conclusion, VAN+CFP should be the preferred empiric regimen in patients with severe DFI.