Increased augmentation index in rheumatoid arthritis and its relationship to coronary artery atherosclerosis.

OBJECTIVE: Arterial stiffness, assessed by the augmentation index and pulse wave velocity, is an independent risk factor for cardiovascular disease. Rheumatoid arthritis (RA) is associated with accelerated atherosclerosis and increased cardiovascular mortality. We examined the hypothesis that augmentation index and pulse wave velocity are increased in RA, and are related to coronary artery atherosclerosis.
METHODS: We measured augmentation index and brachial pulse wave velocity in 117 patients with RA [57 with early (< 6 yrs) and 60 with late disease (> 10 yrs)] and 65 healthy controls. Coronary artery calcification was measured by electron beam computed tomography. Augmentation index and pulse wave velocity were compared in patients with early RA, late RA, and controls, and the association with coronary atherosclerosis was examined.
RESULTS: Patients with late RA had a higher augmentation index (median 33.8%, interquartile range 27.5% 37.0%) than those with early disease (median 27.5%, IQR 21.0% 34.0%) (p = 0.008) and controls (median 27.0%, IQR 20.4% 33.0%) (p < 0.001). After adjusting for height and cardiovascular risk factors, the association between late disease and augmentation index remained significant (p = 0.02). Augmentation index was associated with coronary calcification score (rs = 0.19, p = 0.046), and the association was marginal after adjustment for cardiovascular risk factors, disease status, and disease activity (p = 0.09). There was no significant difference in brachial pulse wave velocity among patients with late (9.2 +/- 1.7 m/s) and early RA (9.1 +/- 1.6 m/s) and controls (8.9 +/- 1.5 m/s) (p = 0.78).
CONCLUSION: Patients with RA have increased augmentation index independent of cardiovascular risk factors. Augmentation index was associated with coronary artery calcification in patients with RA; this was attenuated after adjusting for cardiovascular risk factors.