Between-centre variation in antibiotic therapeutic drug monitoring and obtaining surveillance cultures in Dutch ICUs: A retrospective observational study

Purpose Antimicrobial resistance is a major concern in intensive care units (ICUs), where infections and antibiotic use are common. Antimicrobial stewardship programs (ASPs) promote optimal infectious disease management through interventions such as Therapeutic Drug Monitoring (TDM) and selective digestive/oropharyngeal decontamination (SDD/SOD), but data on ICU-specific quality indicators (QIs) and between-centre variation are limited. This study aimed to evaluate infectious disease management in Dutch ICUs by assessing adherence to, and variation in, TDM and SDD/SOD practices. Methods In this retrospective multi-centre study, infectious disease management was evaluated across eleven ICUs using routine data from 2019 to 2023. One process QI for TDM and two for SDD/SOD administration and surveillance were assessed. QI performance was calculated per ICU, and adjusted variation was quantified using the median odds ratio (MOR) from multilevel logistic regression models. Results Among 64,858 ICU admissions, 78.8% received antibiotics and 35.7% received SDD/SOD. Median performance for timely TDM was 73.6%, with 75.6% for vancomycin, 36.8% for voriconazole, and 23.5% for aminoglycosides. SDD/SOD was administered in 73.9% of admissions, and surveillance cultures were collected in 92.4% of cases when SDD/SOD was administered. Substantial variation was observed between ICUs (MOR = 1.73, 2.42, and 1.23 for TDM, SDD/SOD administration, and SDD/SOD surveillance), which persisted after adjustment for patient characteristics. Conclusions Substantial variation was observed between ICUs, indicating room for quality improvement. This could not be explained by case-mix, which suggests that organizational factors are possible drivers of this variation.