Abstract
Background Vancomycin is a commonly used antibiotic in critically ill patients for various indications. Critical illness imposes pharmacokinetic-pharmacodynamics challenges, which makes optimizing vancomycin in this population cumbersome. Data are scarce on the clinical impact of time to therapeutic trough levels of vancomycin in critically ill patients. This study aims to evaluate the timing to achieve therapeutic trough level of vancomycin on 30-day mortality in critically ill patients. Method A retrospective cohort study was conducted for all adult critically ill patients with confirmed Gram-positive infection who received IV vancomycin between January 1, 2017, and December 31, 2020. We compared early (< 48 h) versus late (>= 48 h) attainment of vancomycin therapeutic trough levels. The primary outcome was the 30-day mortality in critically ill patients. Secondary outcomes were the development of resistant organisms, microorganisms eradication within 4-5 days of vancomycin initiation, acute kidney injury (AKI), and length of stay (LOS). Propensity score-matched (1:1 ratio) used based on patient's age, serum creatinine, and albumin values at baseline. Results A total of 326 patients were included; 110 patients attained the therapeutic trough levels within 48 h of vancomycin initiation. Late achievement of the therapeutic trough levels was associated with higher 30-day mortality (HR: 2.54; 95% CI [1.24-5.22]; p = 0.01). Additionally, patients who achieved therapeutic trough levels of vancomycin late were more likely to develop AKI (OR = 2.59; 95% CI [1.01-6.65]; p = 0.04). Other outcomes were not statistically significant between the two groups. Conclusion Early achievement of vancomycin therapeutic levels in patients with confirmed Gram-positive infection was associated with possible survival benefits.