Evaluation of antibacterial agent use in adult patients at a tertiary-level hospital in Jordan: A comparative analysis of defined daily dose and days of therapy in critical care units

OBJECTIVE: To compare two measures of antibiotic stewardship: Defined Daily Dose (DDD) versus Days of Therapy (DOT). METHODS: Retrospective observational analysis of clinical data for adult ICU patients with antimicrobial exposure recorded from July 2023 to July 2024. The variables collected were the DDD and DOT. The DDD variable was defined according to the World Health Organization (WHO) standards for all antibacterial medications. For the DOT variable, DOTs reflected each day a drug was given, regardless of dose count. For comparability, total DDDs and DOTs were standardized per 100 patient-days using the 6,614 patient-days accrued by the antimicrobial-exposed ICU cohort as the denominator. RESULTS: Over the study duration, 1,024 patients were admitted to adult ICUs, of whom 607 received antimicrobial agents. The overall median total DDD per antimicrobial agent was 64.3 (interquartile range [IQR]: 6.6-530.0), while the corresponding median total DOT was 47.0 (IQR: 6.0-581.5), reflecting considerable variation in absolute antimicrobial measurement across the two methods (Wilcoxon signed-rank test across patient-antimicrobial pairs: V = 130,979, p < 0.001). CONCLUSIONS: DDD and DOT remained strongly correlated but showed clinically meaningful drug-level disagreement in this ICU cohort. DOT provides a clinically interpretable measure of antimicrobial exposure duration in ICU patients because it reflects treatment days irrespective of dose, whereas DDD remains useful for standardized benchmarking across institutions and time periods. The two measures provide complementary information on antimicrobial use and should not be interpreted as substitutes for one another.