Prehypertension increases the risk of atherosclerosis in drug-naive Japanese patients with type 2 diabetes mellitus

Purpose Hypertension is a risk factor of atherosclerotic diseases. However, the importance of prehypertension in Japanese patients with type 2 diabetes mellitus (T2DM) is controversial. The aim of this study was to examine association between prehypertension, hypertension and atherosclerosis in T2DM. Methods We recruited 179 Japanese patients with T2DM, who never took any medication for diabetes, hypertension, dyslipidemia, or atherosclerosis. Intima-media thickness (IMT) of common carotid artery was evaluated by high-resolution B-mode ultrasonography. Results Multiple regression analysis adjusted for age, duration of diabetes, body mass index, HbA1c, fasting C-peptide, triglyceride, HDL-cholesterol, LDL-cholesterol, and estimated glomerular filtration rate showed that systolic blood pressure (SBP), but not diastolic BP, was significantly and positively associated with maximum IMT (IMT-max), mean IMT, and plaque score (beta = 0.28, p<0.001; beta = 0.26, p = 0.047; and beta = 0.25, p = 0.006, respectively). ROC analysis showed that the cut-off value of SBP to detect atherosclerosis (IMT-max 1.8mm, the mean of IMT-max of this subjects) was 133.5 (p = 0.008), while DBP was not useful to detect it (p = 0.433). Then, participants were categorized as normotension (SBP <119 mmHg), prehypertension (SBP 120-139 mmHg), and hypertension (>140 mmHg). Multiple logistic regression analysis adjusted for the variables described above plus gender and smoking showed that prehypertension and hypertension were significantly associated with the increased risk of atherosclerosis [prehypertension; odds ratio (OR) 3.45, 95% confidence interval (CI) 1.11-10.76, p = 0.033, and hypertension; OR 7.29, 95%CI 1.99-26.78, p = 0.003]. Conclusion These findings suggest that prehypertension categorized by SBP is an important risk factor of atherosclerosis independently of conventional risk factors in patients with T2DM.