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

Background Vancomycin-associated nephrotoxicity is a key clinical concern, yet research in elderly patients has predominantly been limited to single-center, small-sample observational studies, lacking systematic evaluation. This study employs a multicenter retrospective design to analyze the current status, risk factors, and outcomes of acute kidney injury (VI-AKI) following vancomycin use in elderly patients, aiming to provide evidence for rational clinical medication practices. Methods The study included elderly patients (> 65y) hospitalized and treated with vancomycin in three hospitals from December 2009 to October 2024. The primary outcome was VI-AKI. Multivariate logistic regression analysis was used to identify independent risk factors for VI-AKI. Results A total of 3762 elderly patients (from 9299 participants) were included. The incidence of VI-AKI was 17.01% (640/3,762). Among VI-AKI patients, 60.8% (389/640) were male, with a median age of 74 years [interquartile range (IQR): 11] and a median body mass index of 22.44 kg/m² (IQR: 4.51). Multivariate logistic regression analysis revealed that age > 75 years (1.63, 1.34–1.98, P  < 0.001), cardiac insufficiency (1.43, 1.13–1.81, P  = 0.003), renal insufficiency (2.49, 1.77–3.50, P  < 0.001), multiple organ failure (3.51, 1.65–7.48, P  = 0.001), hypoproteinemia (1.38, 1.12–1.69, P  = 0.003), ICU admission (1.60, 1.13–2.26, P  = 0.008), sepsis (1.29, 1.01–1.64, P  = 0.043), mean daily dose > 2 g (1.83, 1.33–2.53, P  < 0.001), aminoglycosides use (2.97, 1.57–5.62, P  = 0.001) and piperacillin-tazobactam use (1.50, 1.02–2.20, P  = 0.039) were independent risk factors for VI-AKI. Among the patients developed VI-AKI, the complete renal recovery rate was 21.9% (140/640). Logistic analysis revealed AKI Stage 3 (0.43, 0.22–0.83, P  = 0.012) were independent risk factors for function recovery, while acetylcysteine was protective factor significantly promoted renal function recovery (2.42, 1.25–4.69, P  = 0.09). Conclusion Age > 75years, cardiac insufficiency, renal insufficiency, ICU admission, multiple organ failure, sepsis, hypoproteinemia, mean daily dose > 2 g, concomitant aminoglycosides or piperacillin-tazobactam use may increase the risk of VI-AKI in the elderly. Higher AKI stages were associated with poorer prognosis, and the use of acetylcysteine may have a potential role in improving outcomes. Trial Registration This clinical trial was registered in the Chinese Clinical Trial Registry (ChiCTR) with the identifier ChiCTR2400094474 on 23 December 2024.