Trends and geographical variations in outpatient antimicrobial consumption in Ireland in relation to socio-economic deprivation

Background: Different factors have been associated with changes in antimicrobial consumption rates in Ireland, however the relationship between socio-economic deprivation and antimicrobial consumption has not been explored. The presented ecological analysis explores the temporal and geographical variation in outpatient antimicrobial consumption and socio-economic deprivation in Ireland from January 2015 to March 2022.

Method: Deprivation index (DI) was used as a socio-economic proxy. A multilevel mixed model was applied to explore temporal variation and analyse the longitudinal antimicrobial consumption (DID) in relation to DI. Furthermore, maps were generated based on antimicrobial consumption rates, and spatial autocorrelation analyses were carried out to study geographical variation in antimicrobial consumption rates.

Results: The antimicrobial consumption rates per month varied from 26.2 DID (January 2015) to 22.1 DID (March 2022) showing an overall reduction of 16 %. Overall, total antimicrobial consumption in the multilevel model showed a consistent correlation with higher DI score (6.6 (95%CI 3.9 to 9.3)), and winter season (3.6 (95%CI 3.2 to 3.9)). In contrast, before COVID-19 showed significant lower antimicrobial consumption rates compared to during COVID-19 (-4.0 (95%CI -4.7 to -3.23)). No consistent trends were observed for geographical variation between areas.

Conclusion: Antimicrobial consumption rates decreased from 2015 to 2021 in Ireland. No geographical patterns were observed in antimicrobial consumption rates but associations between deprivation and antimicrobial consumption rates were observed.