Blood pressure is the main determinant of the reflection wave in patients with type 2 diabetes

Augmentation index (AI), the ratio of augmented pressure by the reflection pressure wave to the pulse pressure (PP), is an index of arterial stiffness and central blood pressure (BP). Although type 2 diabetes mellitus (DM) is a major risk factor for atherosclerosis, there is controversy with respect to how DM affects AI. In the present study, we investigated possible determinants of AI in 194 type 2 DM patients (mean age 67+/-9 years). AI was measured in the left radial artery using an automated tonometric method. In a simple correlation analysis, AI showed a positive association with age, and a negative association with body height, body weight, waist circumference, heart rate (HR), plasma glucose, and HbA1c. Women had significantly higher AI than men. Stepwise regression analysis revealed that mean BP (MBP) (beta=0.260, p<0.001), HR (beta=-0.550, p<0.001) and body height (beta=-0.217, p<0.001) were independent determinants of radial AI. Similarly, the second peak of systolic BP (SBP2), an index of central aortic systolic BP (SBP), showed a positive association with age, BMI, waist circumference, MBP and AI, and a negative association with body height. In a separate analysis performed in diabetic patients with treated hypertension (n=123), again, only MBP, HR and body height were significant determinants of radial AI. There was no difference in radial AI and SBP2 among the classes of antihypertensive drugs used. These findings indicate that tight BP control would be effective in reducing the reflection wave and aortic BP, which could independently relate to cardiovascular disease in type 2 diabetic patients.