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Relationship between plasma polymyxin B concentrations and acute kidney injury in critically ill elderly patients: Findings from a prospective study

Year: 2025

Type: article

Abstract: Objective The objective of this study was to determine the relationship between the plasma polymyxin B concentration and renal function in elderly patients. Methods This prospective, case-control, observational study included elderly patients who received polymyxin B therapy and were divided into an acute kidney injury (AKI) group and a non-AKI group based on their renal function. We monitored the pharmacokinetics and pharmacodynamics of polymyxin B, including the minimum plasma concentration (C min ), mean blood drug concentration at steady state (C ss,avg ), and area under the concentration-time curve across 24 h at steady state (AUC ss,24h ) in both study groups. The plasma polymyxin concentration was determined using high-performance liquid chromatography-tandem mass spectrometry. Results The loading doses, C min , C ss,avg , and AUC ss,24h were significantly higher in the AKI group than in the non-AKI group ( p < 0.05). Receiver-operating characteristic curve analysis showed that the optimal cutoff values for predicting AKI were 2.94 mg/L for C min , 4.14 mg/L for C ss,avg , and 99.35 mg·h/L for AUC ss,24h , with corresponding sensitivities and specificities ranging from 78.57% to 82.14%. Conclusion Monitoring plasma polymyxin B concentrations is essential in elderly patients. Keeping the C min below 2.94 mg/L, the C ss,avg below 4.14 mg/L, and the AUC ss,24h below 99.35 mg h/L may help prevent AKI in this population.

Source: Journal of International Medical Research

DOI: 10.1177/03000605251320733