Changes in antibiotic prophylaxis prescribing and infective endocarditis admissions in England and Scotland following changes in national guidance: a quasi-experimental longitudinal study

Background Use of antibiotic prophylaxis (AP) prior to invasive dental procedures (IDPs) to prevent infective endocarditis (IE) fell dramatically in the UK when the National Institute for Health and Care Excellence (NICE) recommended its cessation in 2008. However, guidance implementation by dentists, general medical practitioners (GPs) and others differed in England and Scotland, particularly after 2018 when the Scottish Dental Clinical Effectiveness Programme advised Scottish dentists to consider AP for high-risk individuals. We compared the effects of this differing guidance on AP prescribing and IE-admissions. Methods A quasi-experimental (natural) longitudinal-study design was used to compare aggregated national AP prescribing (2002–2025) and IE-admissions data (1998–2025) for England and Scotland. Interrupted time series and difference-in-differences analyses were used to evaluate changes. Findings AP prescribing fell 93% in England after the 2008 NICE guidelines and remained low (2567 [95% CI 2433–2701] prescriptions/million/annum before 2008 vs 185 [95% CI 165–204] prescriptions/million/annum after 2021/2, p < 0.0001), while IE-admissions increased by 112% (26 [95% CI 25–27] admissions/million/annum before 2008 vs 55 [95% CI 54–56]/million/annum after 2021/2, p < 0.0001). In Scotland, AP prescribing fell less, because GP prescribing replaced some dental prescribing, then rose again after 2018 and finished 2.86 times higher than in England (1884 [95% CI 1816–1952] prescriptions/million before 2008 vs 528 [95% CI 350–705] prescriptions/million after 2021/2). Correspondingly, Scottish IE-admissions rose less (24 [95% CI 23–25] admissions/million before 2008 vs 34 [95% CI 32–37] admissions/million after 2021/2, p < 0.0001) than in England, and English IE-admissions/million ended 61% higher than in Scotland (p < 0.0001). Interpretation Although our data do not establish causality, they suggest that cessation of AP may be followed by a significant increase in IE-admissions compared with policies recommending AP for high-risk individuals. Funding None.