Higher fasting glucose is associated with poorer survival in non-diabetic subjects having ischemia with non-obstructive coronary arteries

Subjects who have ischemia with non-obstructive coronary arteries (INOCA) experience angina pectoris with evidence of myocardial ischemia but without coronary stenosis. Few studies have investigated factors associated with its survival, especially insulin resistance. In this study, subjects with angina pectoris, without known diabetes mellites (DM), and with non-invasive tests showing myocardial ischemia were admitted for coronary angiography (CAG). Those whose CAG did not reveal stenosis and agreed to receive an oral glucose tolerance test (OGTT) 2 weeks after hospital discharge were enrolled for analysis. All-cause mortality was recorded, which served as the outcome of the study. A total of 587 subjects with INOCA, without known DM, and with OGTT data were analyzed. After OGTT and HbA1c tests, 86 subjects (14.7%) were newly diagnosed with DM and 59.8% had pre-DM. The median duration of follow-up was 7.03 years. Thirty-nine subjects died during the follow-up period. The incidence rate of mortality was 9.9 /1000 person-year. Those who died had a higher fasting glucose (101 ± 17 vs. 94 ± 13 mg/dl, p = 0.003) but a lower estimated glomerular filtration rate (eGFR) (54 ± 22 vs. 87 ± 30 ml/min, p < 0.001). In the Cox survival analysis, a higher fasting glucose (hazard ratio 1.053, p = 0.007) was associated with worse mortality for INOCA without DM (N = 501). On the contrary, a higher eGFR (hazard ratio 0.967, p = 0.012) was protective of better survival for non-diabetic INOCA (N = 501). In conclusion, for non-diabetic INOCA, higher fasting glucose was associated with worse mortality and higher eGFR was protective for better survival.