Prehypertension increases the risk of atherosclerosis in drug-naïve 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 (β = 0.28, p<0.001; β = 0.26, p = 0.047; and β = 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.