Diabetes is not a risk factor for myocardial infarction in patients without coronary artery disease
Abstract Background Diabetes is considered a risk factor for myocardial infarction (MI). However, we have previously found that diabetes was not a short-term risk factor for MI in the absence of obstructive coronary artery disease (CAD). Purpose As long-term data are not available, we aimed to assess adverse cardiac events in patients with and without diabetes stratified by CAD up to 11 years after coronary angiography. Methods We conducted a cohort study of patients undergoing coronary angiography from 2003 to 2012 and followed them by cross-linking Danish health registries. Patients were stratified according to the presence/absence of CAD and diabetes. Outcomes included MI, cardiac death, all-cause death, and coronary revascularization. Results A total of 86,202 patients were included (diabetes: n=12,652). Median follow-up was 8.8 years. Using patients with neither CAD nor diabetes as reference (cumulative MI incidence 2.6%), the risk of MI was similar for patients with diabetes alone (3.2%; hazard ratio 1.202, 95% CI: 0.996–1.451), was increased for patients with CAD alone (9.3%; hazard ratio 2.75, 95% CI: 2.52–3.01), and was highest for patients with both CAD and diabetes (12.3%; hazard ratio 3.79, 95% CI: 3.43–4.20), see Figure. Similar associations were observed for cardiac death and coronary revascularization. Conclusions Diabetes patients without CAD by coronary angiography have a similar risk of MI compared to patients with neither CAD nor diabetes. In the presence of CAD, however, diabetes increases the risk of MI. Figure 1 Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): The Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.