The Association of Race and Ethnicity with Disease Expression in Male US Veterans with Rheumatoid Arthritis

TED R. MIKULS, SALAHUDDIN KAZI, DAISHA CIPHER, RODERICK HOOKER, GAIL S. KERR, J. STEUART RICHARDS, and GRANT W. CANNON

ABSTRACT.

Objective. To examine the association of race/ethnicity with measures of disease activity and severity among male US veterans with rheumatoid arthritis (RA).

Methods. Measures of disease activity and severity were examined in a group of US veterans (n = 573) with RA, comparing measures in African American men (n = 79) with Caucasian men (n = 494). Dichotomous variables were compared using logistic regression while continuous variables were examined using linear regression, adjusting for the effects of age, disease duration, and smoking status.

Results. Compared to Caucasians, African Americans were slightly younger (65.0 vs 67.1 yrs; p = 0.09) at enrollment and had a similar age at disease onset (50.5 vs 50.6 years; p = 0.98). After adjusting for age, disease duration, and smoking status, there were no differences based on race/ethnicity in rheumatoid factor positivity, the presence of radiographic changes, physical functioning, swollen joint counts, Disease Activity Score (DAS28), or global well-being scores. In contrast, African Americans were about 50% less likely than Caucasians with RA to have subcutaneous nodules (adjusted OR 0.51, 95% CI 0.30–0.86) and had lower tender joint counts (p = 0.007), associations that were attenuated and not significant with further adjustment for collection site.

Conclusion. With the possible exception of lower rates of rheumatoid nodules and lower tender joint counts in African Americans, there is little evidence to support the existence of important racial/ethnic differences in RA disease expression between African American and Caucasian men. (First Release June 1 2007; J Rheumatol 2007;34:1480-4)

Key Indexing Terms:

RHEUMATOID ARTHRITIS
AFRICAN AMERICAN
CAUCASIAN
NODULES
DISEASE ACTIVITY

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From the Omaha Veterans Affairs Medical Center (VAMC) and University of Nebraska, Omaha, Nebraska; VA North Texas Health Care System and University of Texas Southwestern Medical Center, Dallas, Texas; University of North Texas Health Science Center, Fort Worth, Texas; Washington, DC, VAMC and Georgetown University, Washington, DC; and George E. Wahlen VAMC and University of Utah, Salt Lake City, Utah, USA.

The VARA Registry has been supported by the VA Medical and Research Services and by an unrestricted educational grant from Abbott Laboratories. Dr. Mikuls' work is supported by grants from NIH/NIAMS (K23 AR0500004-01A1) and the Arthritis Foundation (Arthritis Investigator Award).

T.R. Mikuls, MD, MSPH, Omaha Veterans Affairs Medical Center and University of Nebraska; S. Kazi, MBBS; R. Hooker, PA, PhD, VA North Texas Health Care System and University of Texas Southwestern Medical Center; D. Cipher, PhD, University of North Texas Health Science Center; G.S. Kerr, MD; J.S. Richards, MD, Washington, DC, VAMC and Georgetown University; G.W. Cannon, MD, George E. Wahlen VAMC and University of Utah.

Address reprint requests to Dr. T.R. Mikuls, 986270 Nebraska Medical Center, Omaha, NE 68198-6270. E-mail: tmikuls@unmc.edu

Accepted for publication March 1, 2007.

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