Risk of Myocardial Infarction in Patients Without Angiographic Coronary Artery Disease Compared With the General Population.

We examined the 10-year risk of myocardial infarction (MI) and death in patients without obstructive coronary artery disease (CAD) compared with the general population. We conducted a cohort study of every patient without obstructive CAD by coronary angiography (CAG) between 2003 and 2016 in Western Denmark. Patients were matched by gender and age with individuals from the general population of Western Denmark with no history of CAD. End points were MI and death. Ten-year risk differences in cumulative incidence proportions were computed, accounting for the competing risk of death in the case of MI. Unadjusted and adjusted incidence rate ratios (aIRRs) were estimated using conditional Poisson regression. We included 46,467 patients and 234,654 individuals from the general population. Median follow-up was 7.7 years. The 10-year cumulative incidence of MI was 2.40% (95% confidence interval [CI] 2.24 to 2.57) in patients without obstructive CAD in the CAG and 2.70% (95% CI 2.62 to 2.78) in the general population, with a reduced absolute 10-year risk (risk difference -0.30%, 95% CI -0.49 to -0.12) and a reduced aIRR (aIRR 0.70, 95% CI 0.63 to 0.77). Ten-year mortality was higher in patients without obstructive CAD in the CAG (21.44%, 95% CI 20.99 to 21.89) compared with the general population (17.25%, 95% CI 17.06 to 17.44). However, mortality rates were similar after adjustment (aIRR 1.00, 95% CI 0.96 to 1.02). In conclusion, the absence of obstructive CAD according to CAG is associated with a lower risk of MI than in the general population, and similar 10-year mortality.

Diabetes is not a risk factor for myocardial infarction in patients without coronary artery disease: A study from the Western Denmark Heart Registry.

BACKGROUND: Diabetes is considered a risk factor for myocardial infarction. However, we have previously found that diabetes was not a short-term risk factor for myocardial infarction in the absence of obstructive coronary artery disease. 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 coronary artery disease and diabetes. Endpoints included myocardial infarction, cardiac death, all-cause death and coronary revascularization. RESULTS: 86,202 patients were included in total (diabetes: n = 12,652). Median follow-up was 8.8 years. Using patients with neither coronary artery disease nor diabetes as reference (cumulative myocardial infarction incidence 2.6%), the risk of myocardial infarction was low and not substantially increased for patients with diabetes alone (3.2%; hazard ratio 1.202, 95% confidence interval 0.996-1.451), was increased for patients with coronary artery disease alone (9.3%; hazard ratio 2.75, 95% confidence interval 2.52-3.01) and was highest for patients with both coronary artery disease and diabetes (12.3%; hazard ratio 3.79, 95% confidence interval 3.43-4.20). Similar associations were observed for cardiac death and coronary revascularization. CONCLUSION: Diabetes patients without coronary artery disease by coronary angiography have a low risk of myocardial infarction, not substantially increased compared to patients with neither coronary artery disease nor diabetes. In the presence of coronary artery disease, however, diabetes increases the risk of myocardial infarction.