Clinical applicability of urinary creatinine clearance for determining the initial dose of vancomycin in critically ill patients

Introduction: The purpose of this study was to evaluate the clinical applicability of urinary creatinine clearance (CrCl) for determining the initial dose of vancomycin (VCM) in critically ill patients and to assess VCM trough plasma concentration/maintenance daily dose (C/D) ratio in patients with augmented renal clearance (ARC). Methods: As the primary outcome measure, correlations between estimated renal function and the VCM C/D ratio were compared using the following formulas: CrCl, Cockcroft-Gault equation (eCrCl_C-G) and KineticGFR equation (KeGFR). Patients were divided into those with or without changes in renal function. The patients were further classified based on the presence or absence of ARC. The secondary outcome was the comparison of VCM C/D ratio between ARC and Non-ARC patients. Results: A total of 65 patients were enrolled for analysis. In all groups, CrCl tended to correlate better with the VCM C/D ratio than eCrCl_C-G and KeGFR. A significantly lower VCM C/D ratio was observed in patients with persistent ARC than in the Non-ARC group (0.24 versus 0.52 kg/L). Conclusions: The clinical applicability of CrCl for the initial dosing design of VCM in critically ill patients was shown. Furthermore, the results indicated that patients with persistent ARC required a higher VCM dose than Non-ARC patients. Although our findings are limited, they have a value for further verification.