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.