Type 2 diabetes exacerbates changes in blood pressure-independent arterial stiffness: cross-sectional and longitudinal evidence from the SUMMIT study

Abstract

Greater central artery stiffness is observed in people with Type 2 diabetes (T2DM). Elevated blood pressure (BP) and altered arterial wall structure/composition in T2DM are generally considered as main drivers for this alteration. However, because conventional arterial stiffness measures are BP-dependent and as such an influence of BP remains in a measure, it is unclear if greater central artery stiffness is a function of greater BP, or due to changes in the structure and composition of the arterial wall. We aimed to measure BP-independent arterial stiffness (β0) cross-sectionally and longitudinally in T2DM. We studied 753 adults with T2DM (DM+) and 436 adults without (DM-) at baseline (Phase 1), and 310 DM+ and 210 DM- adults at three-year follow-up (Phase 2). We measured carotid-femoral pulse wave velocity and used it to calculate β0. In Phase 1, β0 was significantly greater in DM+ than DM- after adjusting for age and sex [27.5 (26.6-28.3) vs 23.6 (22.4-24.8) au, p<0.001]. Partial correlation analyses after controlling for age and sex showed that β0 was significantly associated with haemoglobin A1c (r=0.15 p<0.001) and heart rate [(HR): r=0.23 p<0.001) in DM+. In Phase 2, percentage-change in β0 was significantly greater in DM+ than DM- [19.5 (14.9-24.0) vs 5.0 (-0.6-10.6) %, p<0.001] after adjusting for age, sex and baseline β0. β0 was greater in DM+ than DM- and increased much more in DM+ than in DM- over three years. This suggests that T2DM exacerbates BP-independent arterial stiffness, and may have a complemental utility to existing arterial stiffness indices.