Objective: Increased arterial stiffness is a risk factor for cardiovascular disease and is a feature associated with diabetes. Pulse wave velocity (PWV) is an accepted index of arterial stiffness and augmentation index (AI) derived from radial applanation tonometry has been advocated as a measurement of arterial stiffness. This study compares the relationship between PWV and AI in people with and without diabetes.
Design and methods: A total of 66 people with diabetes and 66 age-matched non-diabetic controls were studied. Central aortic pressure waves were generated using applanation tonometry over the radial artery and used to calculate AI. Carotid-femoral PWV (PWVcf) was measured simultaneously.
Results: Relative to controls, diabetes was associated with increased pulse pressure (PP) and PWVcf (P < 0.01). In contrast, AI did not differ between groups even after adjustment for heart rate. This observation remained consistent irrespective of diabetes type, arterial site, and the presence or absence of antihypertensive therapy. Multiple regression analysis revealed diabetes to be a significant determinant of PWVcf, but not AI.
Conclusions: PP and PWVcf are increased in people with diabetes, but this is not associated with increased AI. These findings conclusively demonstrate that AI is not a reliable measure of arterial stiffness in people with diabetes.