Correlation between the drug concentration of polymyxin B and polymyxin B-associated acute kidney injury in critically ill patients: A prospective study

In recent years, polymyxin B-associated acute kidney injury (PB-AKI) in critically ill patients has been reported frequently, but polymyxin B (PB) is mainly cleared through non-renal pathways, and the reasons of PB-AKI remain unclear. The aim of this study was to investigate the relationship between the serum concentration of PB and PB-AKI. We conducted a prospective cohort study in an intensive care unit between May 2019 and July 2021. Over the study period, 52 patients were included and divided into an AKI group (n = 26) and a non-AKI group (n = 26). The loading dose of PB in the AKI group was significantly higher than that in the non-AKI group. The C-1/2, C-min, and estimated area under the concentration-time curve (AUC)(0-24) of PB in the AKI group were dramatically increased compared with those in the non-AKI group, but the C-max between the two groups showed no differences. Upon obtaining the ROC curve, the areas for the C-1/2, C-min, and estimated AUC(0-24) were 0.742, 0.710, and 0.710, respectively. The sensitivity was ascertained to be 61.54%, and the specificity was 76.92% when the cutoff value for the estimated AUC(0-24) of 97.72 mg.h/L was used preferentially. The incidence of PB-AKI is high and related to the loading dose of PB. PB-AKI could be predicted when the estimated AUC(0-24) of PB was greater than 97.72 mg.h/L.