Vancomycin dosing design method considering risk factors for nephrotoxicity.

backgroundVancomycin (VCM) induces nephrotoxicity in a dose-dependent manner, and patients with risk factors for nephrotoxicity have been reported to develop nephrotoxicity even within the effective concentration range. In the present study, we investigated measures to set an appropriate AUCss for each case by assessing the risk of developing nephrotoxicity using logistic regression curves, separating patients into a High-risk group with risk factors associated with nephrotoxicity when VCM is used and a Low-risk group without risk factors.

methodsA multivariate logistic regression analysis was used to identify risk factors for nephrotoxicity. The AUCss threshold was selected by a CART analysis and ROC curves, and a logistic regression analysis was used to examine the relationship between AUCss and the probability of developing nephrotoxicity. RESULTS AND DISCUSSION: The incidence of nephrotoxicity was 31.7% (33/104) in the High-risk group and 13.0% (14/108) in the Low-risk group, and was significantly higher in the former (p = 0.001). The AUCss threshold was set at 575 mg·h/L for the High-risk group and 650 mg·h/L for the Low-risk group. The probability of developing nephrotoxicity in the High-risk group (104 patients) was high: AUCss 400 mg·h/L (16.8%), 500 mg·h/L (23.3%), and 575 mg·h/L (29.3%). The target concentration range was newly set at 400 ≤ AUCss < 500, suggesting that the target AUCss needs to be considered for each patient based on the balance between therapeutic efficacy and the prevention of adverse effects. The probability of developing nephrotoxicity in the Low-risk group (108 patients) was AUCss 500 mg·h/L (4.7%), 575 mg·h/L (8.4%), and 650 mg·h/L (14.6%). Since the Low-risk group has a high safety profile, the target concentration range was newly set at 400 ≤ AUCss < 650, suggesting the safe administration of the drug up to AUCss 650 mg·h/L while aiming for AUCss 600 mg·h/L from the initial dose design.

conclusionIn the present study, the risk of nephrotoxicity for each AUCss was quantitatively analyzed using logistic regression curves for the High- and Low-risk groups. This allowed for the proposal of strategic individual target concentrations based on the balance between risk and benefit.