The association of race and ethnicity with disease expression in male US veterans with rheumatoid arthritis.

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.