The prognostic effect of known and newly detected type 2 diabetes in patients with acute coronary syndrome

Background: Dysglycemia is a well-established risk factor of coronary artery disease. Less is known of the prognostic effect of dysglycemia in acute coronary syndromes (ACSs). The aim of this study was to evaluate the long-term outcome of patients with ACSs according to glucometabolic categories. Methods: Patients with ACSs were consecutively included in the study. Among those with no previous history of type 2 diabetes (T2DM) glucose metabolism was evaluated with fasting glucose in plasma, glycated hemoglobin and a standard 2-h oral glucose tolerance test. Patients were classified having normal glucose metabolism, prediabetes, newly detected T2DM (nT2DM) and previously known T2DM (kT2DM). The clinical outcome parameters were death or myocardial infarction and other major adverse cardiac events (MACEs). Results: A total of 372 ACS patients (male 75.8%, 65.1 years (SD: 11.8)) constituted the study population. The proportion diagnosed with normal glucose metabolism, prediabetes, nT2DM and kT2DM was 20.7%, 46.5%, 6.2% and 26.6%, respectively. The mean follow-up period was 2.9 years. Patients with prediabetes, nT2DM and kT2DM had a hazard ratio of 5.8 (95% confidence interval (CI) 0.8–44.6), 10.9 (95% CI 1.2–98.3) and 14.9 (95% CI 2.0–113.7), respectively, for death/myocardial infarction and 1.4 (95% CI 0.6–3.1), 2.9 (95% CI 1.1–8.0) and 3.3 (95% CI 1.5–7.6), respectively, for a composite of MACEs. Conclusion: Patients with ACS and nT2DM or kT2DM were at increased risk of death/myocardial infarction and MACE compared with patients with normal glucose metabolism after approximately three years of follow-up.