The effect of body mass index and creatinine clearance on serum trough concentration of vancomycin in adult patients

BACKGROUND: The aim of this study was to evaluate the influence of patient body mass index (BMI) and estimated creatinine clearance (CrCl) on serum vancomycin concentrations to define a possible optimal dosage regimen in overweight patients based on data obtained during therapeutic drug monitoring. METHODS: This retrospective study used data collected from January 2017 to January 2019. Adult patients (n = 204) received vancomycin treatment at a dose of 1000 mg every 12 h and underwent serum monitoring. Data collected included patient disease category, sex, age, height, weight, vancomycin concentrations, and serum creatinine. The CrCl values were estimated using the Cockcroft-Gault formula. In this study, statistical comparisons were performed on the results of patients according to serum vancomycin concentration. RESULTS: Serum vancomycin concentration was significantly related to BMI (P < 0.001) and CrCl (P < 0.05) in adult patients. Furthermore, the trough serum vancomycin concentration showed a logarithmic correlation with BMI (R = − 0.5108, 95% CI: − 0.6082 to − 0.3982, P < 0.001) and CrCl (R = − 0.5739, 95% CI: − 0.6616 to − 0.4707, P < 0.001). The multivariate analysis showed that BMI and CrCl are independent contributors to the trough vancomycin concentration. Moreover, some of the patients with higher BMI (≥ 24 kg/m(2)) met the goal trough concentration after an adjustment from 1000 mg every 12 h to 1000 mg every 8 h. CONCLUSIONS: Serum vancomycin concentration decreases progressively with increasing BMI and the augmentation in CrCl in adult patients. The trough concentration of vancomycin should be continuously monitored for patients with a BMI ≥ 24 kg/m(2), and the dosage regimen should be adjusted to reach the target trough concentration in these patients to reduce the impact of BMI.