Inequalities in the provision of guideline-directed medical therapy following myocardial infarction: a cohort study

Following myocardial infarction (MI), therapies are recommended that reduce risk and prevent future cardiovascular events. Trends in the provision of guideline-directed medical therapies by sex, age, ethnicity and socioeconomic deprivation status may help identify opportunities to reduce inequalities in post-MI care. This cohort study using linked routine healthcare data included patients with MI in South-East Scotland (1 April 2009 to 31st of July 2021). Multivariable logistic regression models with a generalized estimating equation approach were used to assess the association between each sociodemographic factor and the provision of three guideline-directed medical therapies (anti-platelet or anti-thrombotic agent, lipid-lowering therapy and renin-angiotensin system blocker) at 3-, 12-, and 18-months post-discharge. Multivariable cause-specific Cox proportional hazard models were used to evaluate medication status and risk of a composite of non-fatal myocardial infarction, non-fatal stroke, or cardiovascular death across sociodemographic subgroups. The study population comprised 7,926 patients (35% female, mean age 65 [SD 13] years). At 3 months, 5,393 (68%) patients were receiving all three guideline-directed medical therapies. Women (adjusted odds ratio at 3 months [aOR 0.69, 95% confidence interval 0.62 to 0.77]) and patients < 50 years (aOR 0.77, 95% confidence interval 0.65 to 0.89) and > 70 years (aOR 0.58, 95% confidence interval 0.51 to 0.65) were less likely to be receiving all three guideline-directed medical therapies at 3 months with similar observations at 12 and 18 months. No differences were observed by ethnicity and socioeconomic groups across the three time points. Patients receiving all three or one/two guideline-directed medical therapies had a lower risk of future cardiovascular events compared to those not receiving any, with this effect being consistent across all subgroups and time points. Women, and both younger and older patients are less likely to be receiving guideline-directed medical therapy following MI, despite its benefit in reducing future cardiovascular events. Targeted strategies to increase provision of secondary prevention in these groups are needed to reduce inequalities and improve post-MI care.