Increased Augmentation Index in Rheumatoid Arthritis and Its Relationship to Coronary Artery Atherosclerosis

INGRID AVALOS, CECILIA P. CHUNG, ANNETTE OESER, TEBEB GEBRETSADIK, AYUMI SHINTANI, DANIEL KURNIK, PAOLO RAGGI, TUULIKKI SOKKA, THEODORE PINCUS, and C. MICHAEL STEIN

ABSTRACT.

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 (r_s = 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. (First Release Nov 15 2007; J Rheumatol 2007;34:2388-94)

Key Indexing Terms:

AUGMENTATION INDEX
RHEUMATOID ARTHRITIS
CORONARY ARTERY ATHEROSCLEROSIS

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From the Department of Medicine, Department of Pharmacology, and Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee; and Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia, USA.

Supported by grants HL04012, HL67964, and GM5MO1-RR00095 from the US National Institutes of Health. Dr. Avalos was partly funded by the American College of Rheumatology/REF Lupus Investigator Fellowship Award.

I. Avalos, MD; C.P. Chung, MD, MPH; A. Oeser, BS; T. Sokka, MD; T. Pincus, MD, Department of Medicine; T. Gebretsadik, MPH; A. Shintani, MPH, PhD, Department of Biostatistics; D. Kurnik, MD; C.M. Stein, MD, Departments of Medicine and Pharmacology, Vanderbilt University School of Medicine; P. Raggi, MD, Division of Cardiology, Emory University School of Medicine.

Address reprint requests to Dr. I. Avalos, Division of Rheumatology and Clinical Pharmacology, T-3219 MCN, Vanderbilt University School of Medicine, 1161 21st Ave. South, Nashville, TN 37232-2681. E-mail: ingrid.avalos@vanderbilt.edu

Accepted for publication August 29, 2007.

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