Antibiotic use and deprivation: An analysis of Welsh primary care antibiotic prescribing data by socioeconomic status

Objectives: To examine the association between socioeconomic status (SES) and antibiotic prescribing, controlling for the presence of common chronic conditions and other potential confounders and variation amongst GP practices and clusters. Methods: This was an electronic cohort study using linked GP and Welsh Index of Multiple Deprivation (WIMD) data. The setting was GP practices contributing to the Secure Anonymised Information Linkage (SAIL) Databank 2013-17. The study involved 2.9 million patients nested within 339 GP practices, nested within 67 GP clusters. Results: Approximately 9 million oral antibiotics were prescribed between 2013 and 2017. Antibiotic prescribing rates were associated with WIMD quintile, with more deprived populations receiving more antibiotics. This association persisted after controlling for patient demographics, smoking, chronic conditions and clustering by GP practice and cluster, with those in the most deprived quintile receiving 18% more antibiotic prescriptions than those in the least deprived quintile (incidence rate ratio = 1.18; 95% CI = 1.181-1.187). We found substantial unexplained variation in antibiotic prescribing rates between GP practices [intra-cluster correlation (ICC) = 47.31%] and GP clusters (ICC = 12.88%) in the null model, which reduced to ICCs of 3.50% and 0.85% for GP practices and GP clusters, respectively, in the final adjusted model. Conclusions: Antibiotic prescribing in primary care is increased in areas of greater SES deprivation and this is not explained by differences in the presence of common chronic conditions or smoking status. Substantial unexplained variation in prescribing supports the need for ongoing antimicrobial stewardship initiatives.