Association of diabetes mellitus with clinical outcomes in patients with different coronary artery stenosis

BACKGROUND: It has been demonstrated that patients with type 2 diabetes mellitus (DM) is associated with increased cardiovascular risk. However, little is known regarding the long-term prognosis in diabetic patients who experience mild-to-intermediate coronary artery stenosis (CAS). This study was to assess the clinical outcomes of diabetic patients with different severity of CAS. METHODS: We consecutively enrolled 10,940 patients hospitalized due to angina-like chest pain and followed up for major adverse cardiovascular events (MACEs) covering cardiac death, myocardial infarction, ischemic stroke, unplanned coronary revascularization and angina-related hospitalization. According to coronary angiography, patients were divided into non-obstructive CAS (NOCAS, < 50% stenosis), intermediate CAS (ICAS, 50–69% stenosis), and severe CAS (SCAS, 70–100% stenosis) subgroups, and were further categorized into six groups as NOCAS with DM and non-DM, ICAS with DM and non-DM, and SCAS with DM and non-DM. RESULTS: During a median follow-up of 40 months, 1,017 (11.1%) MACEs occurred. In patients with ICAS or SCAS, the incidence of events was higher when patients coexisted with DM (p < 0.05, respectively). In subgroup analyses, patients with ICAS and DM, SCAS and non-DM, SCAS and DM had increased risk of events [adjusted hazard ratio (HR): 1.709, 95% confidence interval (CI) 1.106–2.641, p = 0.016; HR: 1.911, 95% CI 1.460–2.501, p < 0.001; HR: 2.053, 95% CI 1.514–2.782, p < 0.001] compared to ones with NOCAS and non-DM. Besides, the Kaplan–Meier curves indicated the highest risk of MACEs in patients with SCAS and DM than others (p < 0.001). CONCLUSIONS: Diabetic patients with ICAS had the worse outcome, which was comparable to patients with SCAS alone.