Endothelial dysfunction in prediabetes and diabetes mellitus in patients with normal coronary arteries

BACKGROUND: Diabetes mellitus (DM) is a global health issue associated with increased cardiovascular disease risk. Endothelial dysfunction is a known precursor to atherosclerosis and cardiovascular disease, and its role in the pathogenesis of DM complications is well-documented. There is limited information in the evaluation of endothelial function in prediabetic patients using flow-mediated dilation (FMD), and studies have not excluded patients with known atherosclerosis or coronary artery disease. Thus, in this study, we aimed to evaluate the endothelial functions using FMD from the brachial artery of DM and prediabetes patients who had normal coronary arteries. METHODS: This study included 73 participants: 25 with DM, 25 with prediabetes, and 23 normoglycemic controls, all with normal coronary arteries on angiography. FMD measurements were conducted following established protocols, and statistical analysis was performed using standard methods to compare FMD levels among groups. RESULTS: The groups were comparable in clinical and demographic characteristics, except for fasting plasma glucose levels. Significant differences in FMD levels were observed: 10.1% in the DM group, 16.5% in the prediabetes group, and 14.8% in the control group (P = 0.004). Diabetic patients had significantly lower FMD levels than both prediabetic and normoglycemic individuals. No significant difference in FMD was found between prediabetic and control groups. CONCLUSIONS: Diabetic patients exhibited significant endothelial dysfunction compared to normoglycemic individuals, while prediabetic patients did not show similar dysfunction. These findings suggest a window of opportunity in the prediabetic stage for early intervention to prevent advanced endothelial dysfunction. TRIAL REGISTRATION NUMBER: ISRCTN Registry ISRCTN15351014. Registry date: 23/09/2024. Retrospectively registered.