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.