Diabetes and coronary risk equivalency – a population-based cohort study from Western Denmark

Abstract

Abstract Background Diabetes is associated with an increased risk of cardiovascular disease. Accordingly, guidelines recommend extensive management of cardiovascular risk factors in patients with diabetes. Diabetes has previously thought to carry the same high cardiovascular risk as already having coronary heart disease. It is, however, unknown if the intensified focus on prophylactic treatment has changed the risk of myocardial infarction and ischemic stroke in contemporary practice. Aims We aimed to examine whether diabetes remains a cardiovascular risk equivalent to coronary heart disease under the contemporary treatment regimen. Methods We included every person residing in Western Denmark on January 1, 2012, aged 50–89 years. The cohort was stratified by diabetes and coronary heart disease (defined as previous myocardial infarction, percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), or coronary artery disease documented by coronary angiography). The four groups were followed for up to seven years after inclusion. Outcomes were myocardial infarction, ischemic stroke, cardiac death, and all-cause death. Patients with coronary heart disease only were compared to patients with diabetes only using a multivariable Cox regression model. Results We included 1,111,456 persons residing in Western Denmark on January 1, 2012, of whom 86.1% had neither diabetes nor coronary heart disease, 7.5% had diabetes only, 5.0% only had history of coronary heart disease, 1.4% had both diabetes and coronary heart disease. Patients with diabetes only less likely to be in antithrombotic treatment, lipid-lowering treatment, and antihypertensive treatment compared to patients with coronary heart disease only. Compared to patients with diabetes only (Figure 1), coronary heart disease was associated with an increased risk of myocardial infarction (adjusted HR 1.73, 95% CI 1.65–1.82) and cardiac death (adjusted HR 1.40, 95% 1.32–1.48). However, coronary heart disease only was associated with a reduced risk of ischemic stroke (adjusted HR 0.83, 95% CI 0.79–0.87) and all-cause mortality (adjusted HR 0.76, 95% CI 0.74–0.77) compared to diabetes only (Figure 1). Conclusions In contemporary practice in Denmark, patients with diabetes only have a lower risk of myocardial infarction or cardiac death than observed in non-diabetic patients with verified coronary heart disease. On the contrary, patients with diabetes only have a greater risk ischemic stroke and al–cause mortality than coronary heart disease only. Thus, diabetes is not a uniform cardiovascular risk equivalent to coronary heart disease, but depends on the given outcome. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark