Trends in hospital antibacterial consumption: a retrospective analysis of reimbursement data, Belgium 2017 to 2022

Background: The COVID-19 pandemic has challenged efforts to optimise rational antibacterial use due to uncertainties in treatment protocols. Aim: We inves-tigated the impact of COVID-19 on hospital antibac-terial consumption in Belgium from 2017 to 2022, relative to the general and hospitalised population. Methods: We analysed national reimbursement data using defined daily doses (DDD) and three metrics: DDD/1,000 inhabitants/day (DID), DDD/1,000 patient days (PD) and DDD/1,000 admissions. We performed linear regressions to analyse 6-year trends (2017– 2022) and estimated predicted consumption from 2020 to 2022 using the compound annual growth rate from 2017 to 2019. To assess the impact of COVID-19, we compared observed and predicted relative changes in antibacterial consumption between 2019 (pre-pandemic) and 2020 (early pandemic) and between 2019 and 2022 (late pandemic). Results: From 2019 to 2020, hospital antibacterial consumption (anatomi-cal therapeutic chemical (ATC) J01) decreased by 12% in DID but increased by 5% and 7% in DDD/1,000 PD and DDD/1,000 admissions, respectively. From 2017 to 2022, systemic antibacterials consumption declined significantly only when expressed in DID. Although all systemic antibacterial subclasses were used less than predicted between 2020 and 2022 when expressed in DID, hospital-based metrics showed higher consumption, except for macrolides and amphenicols. Broad-spectrum antibacterial consumption decreased from 2017 to 2022 when expressed in DID but fluctuated with hospital metrics, peaking in 2020, and exceeded forecasts. Conclusion: COVID-19 altered trends in hospital antibacterial consumption, with contrasting pat-terns depending on the metric used, underline the importance of hospital-specific surveillance to support targeted stewardship and preparedness efforts.