Risk of Polymyxin B-induced Acute Kidney Injury in Non-adjusted Dose Versus Adjusted Dose based on Renal Function: a retrospective cohort study

Background This study aimed to observe the difference in risk of polymyxin B-induced acute kidney injury with or without dose adjustment by patients’ renal function. Method A retrospective cohort analysis was carried out for patients who were treated with polymyxin B in Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine from November 2018 to October 2019. Patients were divided into adjusted dosage group and non-adjusted dosage group depended on dosage adjustment with renal function or not. A comparison of acute kidney injury incidence between the two groups was the primary outcome of this research. The secondary outcome included hospital length of stay, microbiological cure, clinical cure, and 30-day mortality. Result A total of 115 patients met the requirements of this study and were included in the analysis. Thirty-five patients were included in the non-adjusted dosage group and 80 in the adjusted dosage group. Patients from both groups had similar characteristics. The total daily dose of polymyxin B in the Non-adjusted dosage group was significantly higher than the adjusted dosage group (1.98 mg/kg/d vs 1.59 mg/kg/d, P =0.001). For the primary outcome of this research, no significant difference in the incidence of acute kidney injury was observed in these two groups (47.5% vs 37.14%, P =0.304), as well as the secondary outcomes, including hospital length of stay, microbiological cure, clinical cure, 30-day mortality. Conclusion Dosing adjustment renally could not lower the risk of polymyxin B-induced acute kidney injury significantly. A non-adjusted dosing strategy of polymyxin B is recommended when patients suffered from various levels of renal impairment.