Why the radial augmentation index is low in patients with diabetes: The J-HOP study.

Abstract Background Radial augmentation index (rAI), a marker of aortic wave reflection, is usually lower in patients with diabetes (DM) than in non-DM subjects, even though atherosclerotic change is advanced in DM. Objective We sought to explore why rAI in DM is lower than in non-DM. Methods We performed radial applanation tonometry in 1787 subjects who had at least one cardiovascular risk factor. The rAI was defined as [late systolic shoulder pressure amplitude (PP2)]/[radial pulse pressure (rPP)]. The late systolic shoulder blood pressure (SBP2) and PP2 of a radial pressure wave were used as estimates of the central SBP and PP (cPP), respectively. Results The age (65.8 ± 9.8 vs. 65.8 ± 12.1 yrs) and mean brachial SBP (141 ± 16 vs. 141 ± 17 mmHg) were similar between the DM and non-DM groups. The rAI was significantly lower in the DM group (83.3 ± 14.1 vs. 87.3 ± 15.7%, p p p  = 0.019) were significantly greater in the DM group than in the non-DM group. In multivariable analyses adjusting for covariates, the significant determinants of rAI were the estimated glomerular filtration rate (eGFR) (β = 0.17, p p Conclusions The lower rAI in DM associated with higher cPP compared to non-DM suggests proximal conduit–predominant arterial stiffening causing reduced reflection coefficients at systemic reflection sites. As renal function decreases, a cPP increase may overcome the increase of augmentation pressure in the DM group.