Impact of prediabetes on long-term cardiovascular outcomes in patients with myocardial infarction with nonobstructive coronary arteries

Background Abnormal glucose metabolism including diabetes (DM) and prediabetes (pre-DM) have been reported as predictors of poorer outcomes after acute myocardial infarction (AMI). However, the prognostic value of pre-DM in patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear. Methods A total of 1179 MINOCA patients were prospectively recruited and divided into normoglycemia (NG), pre-DM, and DM groups according to glycated hemoglobin (HbA 1c ) levels or past history. The primary endpoint was a composite of major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, nonfatal stroke, revascularization and hospitalization for unstable angina or heart failure. Kaplan–Meier and Cox regression analyses were performed. Results Patients with pre-DM and DM had a significantly higher incidence of MACE compared with NG group (10.8%, 16.1%, 19.4%; p = 0.003) over the median follow-up of 41.7 months. After multivariate adjustment, both pre-DM and DM were significantly associated with an increased risk of MACE (NG as reference; pre-DM: 1.45, 95% CI 1.03–2.09, p = 0.042; DM: HR 1.79, 95% CI 1.20–2.66, p = 0.005). At subgroup analysis, pre-DM remained a robust risk factor of MACE compared to NG. In addition, pre-DM had a similar impact as DM on long-term prognosis in patients with MINOCA. Conclusions Pre-DM defined as raised HbA 1c was associated with a poor prognosis in patients with MINOCA. Routine assessment of HbA 1c enables an early recognition of pre-DM and thus may facilitate risk stratification in this specific population.