Impact of hypertension on various markers of subclinical atherosclerosis in early type 2 diabetes

BACKGROUND: Presence of Diabetes Mellitus increases the risk of subclinical atherosclerosis. In this study was aimed to determine the influence of hypertension (HTN) on surrogate markers of atherosclerosis in a population of patients with early type 2 diabetes. METHODS: 125 diabetic subjects drawn from Dr. Shariati outpatient’s clinic list and 153 non- diabetic subjects who were the relatives in law of diabetic participants were recruited. Participants with type 2 diabetes were free of clinical evidence of cardiovascular disease and renal involvement. Two groups of diabetic and control were further divided into two subgroups of hypertensive (known case of HTN or blood pressure ≥140/90 mmHg) and normotensive, and anthropometric characteristics, metabolic biomarkers as well as markers of subclinical atherosclerosis including Carotid intima media thickness (CIMT), flow mediated dilation (FMD) and Ankle Brachial Index (ABI) were measured. RESULTS: Diabetic group with a mean age of 49.9 ± 7.5 years had significantly higher CIMT (0.64 ± 0.14 vs 0.76 ± 0.19, p = 0.001) and lower FMD (16.5 ± 8.1 vs 13.3 ± 7.1, p = 0.003) and ABI (1.2 ± 0.1 vs 1.1 ± 0.1, p = 0.01) than control with mean age of 52.9 ± 10.1 years. 34% of control and 59.2% of diabetic were hypertensive. Fasting blood sugar, insulin levels and calculated insulin resistance index of HOMA IR. of hypertensive subjects were higher than normotensive subjects in both groups of diabetic and non-diabetic. Similar pattern was presented for measured inflammatory mediators of hs-CRP and IL-6. Among subclinical atherosclerosis markers, only CIMT was significantly different between hypertensive and normotensive subjects in both groups. In adjusted linear regression analysis, a constant significant association existed between age and CIMT, ABI and FMD in non-diabetic, while in diabetic, age only correlated with CIMT and not the other two markers. In multiple regression model, HTN was recognized as a risk factor for increasing CIMT (OR = 2.93, 95% CI = 1.03-8.33, p = 0.04) but not attenuating FMD or ABI. CONCLUSIONS: Since FMD and CIMT may measure a different stage of subclinical atherosclerosis in diabetic patients, influence of HTN on these markers might be different.