Incidence and risk factors of vancomycin-associated nephrotoxicity among neonates in the intensive care unit: a retrospective cohort study

BACKGROUND: Vancomycin-induced nephrotoxicity is associated with an increased risk of neonatal mortality and prolonged neonatal intensive care unit (NICU) stay. This retrospective cohort study aimed to assess the incidence of vancomycin-associated nephrotoxicity and its risk factors in neonates. METHODS: The study included neonates admitted to the NICU of the Maternity and Children Hospital (Makkah, Saudi Arabia) from January 2018 to December 2020 who received intravenous vancomycin for more than 48 h. The primary outcome was the incidence of newly developed acute kidney injury (AKI) after the initiation of vancomycin therapy, defined according to the neonatal modified Kidney Disease: Improving Global Outcomes criteria. Analyses included AKI incidence, comparison of clinical parameters between neonates with and without AKI, and multivariable logistic regression to identify predictors of AKI and mortality. RESULTS: Among 362 neonates treated with vancomycin, 11.3% developed AKI. Neonates with AKI had a lower postmenstrual age (31.3 vs. 34.1 weeks, p = 0.01) and higher rates of extreme prematurity (31.7% vs. 14.3%, p = 0.02) and extremely low birth weight (43.9% vs. 18.7%, p = 0.00). Vancomycin trough levels > 15 mg/L were more frequent in the AKI group (26.8%, 11/41) than in others (11.8%, 35/321) (p = 0.00). Only one-third of vancomycin trough measurements were obtained according to guideline-recommended timing. In multivariable analysis, each additional week of postmenstrual age was independently associated with a 10% reduction in the odds of AKI (OR 0.90; p = 0.00). Higher weight was associated with lower mortality (OR = 0.26; p < 0.001), while AKI incidence was associated with increased mortality (OR = 5.88; p < 0.001). Caffeine citrate use was associated with lower odds of mortality, but was not associated with AKI (OR = 0.21; p < 0.001). CONCLUSION: Lower postmenstrual age independently predicted vancomycin-associated AKI. Lower neonatal weight and AKI were associated with increased mortality, reinforcing the importance of individualized monitoring during vancomycin therapy.