From Initiation to Recovery: A Longitudinal Analysis of Polymyxin B-Induced Kidney Injury in Clinical Practice

Polymyxin B (PMB) is an antibiotic used to treat severe infections, but its use is associated with nephrotoxicity. Identifying risk factors for PMB-associated nephrotoxicity is essential for improving patient outcomes.

This study aimed to identify risk factors for PMB-associated nephrotoxicity and evaluate their impact on renal function recovery.

A retrospective analysis was conducted on patients who received PMB therapy at the Second Xiangya Hospital, Central South University, from August 2022 to August 2023. Univariable and multivariable logistic regression analyses were performed to assess risk factors for acute kidney injury (AKI) and factors influencing renal recovery. AKI was defined and staged according to the KDIGO criteria based on serum creatinine changes.

Of the 325 patients treated with intravenous PMB, 112 (34.5%) developed AKI. Independent risk factors for PMB-associated AKI included use of vancomycin (RR=1.398, P=0.027), use of aminoglycosides (RR=2.047, P=0.018), use of amphotericin B (RR=1.834, P=0.006), use of furosemide (>20 mg/day) (RR=1.495, P=0.004), and a higher loading dose of PMB (RR=1.004, P=0.004). The median time to AKI onset was 7 days (IQR: 3-12). Renal recovery occurred in 41.1% of AKI patients, and the use of vasoactive agents was negatively associated with recovery, likely reflecting underlying hemodynamic instability rather than a direct nephrotoxic effect (OR=0.298, P=0.013).

Key risk factors for PMB-associated AKI included the use of vancomycin, aminoglycosides, amphotericin B, high-dose furosemide (>20 mg/day), and the loading dose of PMB. Close monitoring of serum creatinine within the first week of PMB therapy is crucial for improving outcomes. Clinicians should minimize concurrent nephrotoxic agents where feasible and prioritizing rapid hemodynamic stabilization in patients with shock to optimize renal recovery.