Vancomycin-induced acute kidney injury in older Chinese patients: a multicenter retrospective cohort study.

Background: Vancomycin-associated nephrotoxicity remains a major clinical concern, yet evidence in older patients is limited and largely derived from small single-center studies. This multicenter study aimed to evaluate the incidence, risk factors, and outcomes of vancomycin-induced acute kidney injury (VI-AKI).

Methods: In this retrospective cohort study, patients aged ≥ 65 years who received vancomycin at three tertiary hospitals in Shanghai between 2009 and 2024 were included. AKI was defined according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Multivariable logistic regression was performed to identify independent risk factors. The primary outcome was VI-AKI incidence; secondary outcomes included renal recovery and all-cause mortality. A predefined subgroup analysis assessed the association between vancomycin trough concentrations and VI-AKI in patients undergoing therapeutic drug monitoring (TDM).

Results: Among 3,762 patients, VI-AKI occurred in 640 (17.0%). Independent risk factors included age > 75 years, heart failure, baseline renal insufficiency, multiple organ failure, hypoproteinemia, intensive care unit admission, sepsis, vancomycin dose > 2 g/day, and concomitant use of aminoglycosides or piperacillin-tazobactam (all P < 0.05). Complete renal recovery occurred in 21.9% of patients and was less likely in those with stage 3 AKI (OR 0.43, P = 0.012), while acetylcysteine use was associated with a higher likelihood of recovery (OR 2.42, P = 0.009). In the TDM subgroup (n = 433), VI-AKI incidence was 25.9%, and trough concentrations ≥ 17.3 mg/L were independently associated with increased risk (OR 3.02, P < 0.001).

Conclusion: VI-AKI is common in older adults receiving vancomycin and is associated with multiple clinical and treatment-related factors. The low rate of renal recovery underscores the need for early risk stratification and optimized therapeutic drug monitoring in this population.

Trial registration: This clinical trial was registered in the Chinese Clinical Trial Registry (ChiCTR) with the identifier ChiCTR2400094474 on 23 December 2024.