Vancomycin-Induced AKI in Adult Patients With Oncological Diseases: Bridging Diagnostic Criteria Gaps With Tailored Dosing Strategies in a Prospective Cohort Study

BACKGROUND: The aim of this study was to (1) determine the incidence of acute kidney injury (AKI) in patients with oncological diseases and identify its probable causes, (2) estimate the pharmacokinetic (PK) parameters in this population, and (3) propose vancomycin dosage regimens to support safer dosing in nontherapeutic drug monitoring settings. METHODS: The authors conducted a prospective observational cohort study involving 334 adult patients with oncological diseases (406 vancomycin treatment courses) at a tertiary cancer center in Brazil. Vancomycin was administered using a Bayesian AUC-guided protocol. AKI was defined using the RIFLE criteria and adjudicated by a multidisciplinary team to determine probable vancomycin attribution. Linear regression was used to estimate the PK parameters and propose a practical dosing regimen for resource-limited settings without therapeutic drug monitoring. RESULTS: AKI occurred in 15% (62/406) of vancomycin courses, with 34% of the events occurring within the first 24 hours of therapy initiation. After excluding early-onset and non-drug-related AKI, the incidence of vancomycin-induced acute kidney injury was 4.9%. A wide trough variability (5.35-20.11 mg/L) was observed for AUC values of 400-500 mg*h/L. Multiple linear regression showed that CrCl, intensive care unit admission, and oncohematological status independently influenced PK parameters. Stratified maintenance dose ranges were described, offering potential guidance for empirical dosing in therapeutic drug monitoring-limited settings. CONCLUSIONS: The incidence of vancomycin-induced acute kidney injury in this oncological cohort was 4.9%. CrCl, intensive care unit admission, and type of oncological disease significantly influenced the PK parameters. These findings support the development of context-specific dosing guidance but require external validation before implementation in clinical practice.