Risk of myocardial infarction in men and women with type 2 diabetes in the UK: a cohort study using the General Practice Research Database

Aims/hypothesis Our primary aim was to establish reliable and generalisable estimates of the risk of myocardial infarction (MI) for men and women with type 2 diabetes in the UK compared with people without diabetes. Our secondary aim was to investigate how the MI risk associated with diabetes differs between men and women. Methods A cohort study using the General Practice Research Database (1992-1999) was carried out, selecting 40,727 patients with type 2 diabetes and 194,913 age and sex-matched patients without diabetes. Rates of MI in men and women with and without diabetes were derived, as were hazard ratios for MI adjusted for known risk factors. Results The rate of MI in men with type 2 diabetes was 19.74 (95% CI 18.83-20.69) per 1,000 person-years compared with 16.18 (95% CI 15.33-17.08) per 1,000 person-years in women with type 2 diabetes. The overall adjusted relative risk of MI in diabetes versus no diabetes was 2.13 (95% CI 2.01-2.26) in men and 2.95 (95% CI 2.75-3.17) in women and decreased with age in both sexes. Women with type 2 diabetes aged 35 to 54 years were at almost five times the risk of MI compared with women of the same age without diabetes (HR 4.86 [95% CI 2.78-8.51]). Conclusions/interpretation This study has demonstrated that women with type 2 diabetes are at a much greater relative risk of MI than men even when adjusted for risk factors.