A clinical and serologic comparison of African American and Caucasian patients with systemic sclerosis

Epidemiology studies suggest that systemic sclerosis (SSc) is more common, occurs at a younger age, and is more severe in African Americans than Caucasians. However, the scleroderma autoantibody profile is very different between these 2 ethnic groups. This study was undertaken to examine the demographic and disease features, frequency and severity of internal organ system involvement, and survival in African American patients compared to Caucasian patients with SSc, giving particular attention to their serum autoantibody profiles.

Demographic features, clinical characteristics, autoantibody profile, organ involvement, and survival were studied in consecutive African American and Caucasian patients with SSc whose visits were recorded between 1972 and 2007 as part of the Pittsburgh Scleroderma Database. The Medsger Severity Score for SSc was used to determine the severity of disease.

African American patients were more likely to have anti-topoisomerase I (anti-topo I), anti-U1 RNP, and anti-U3 RNP autoantibodies. In comparing African American and Caucasian patients with these antibodies, pulmonary fibrosis was found to be more frequent and more severe, and the rate of survival was decreased, in African American patients with anti-topo I antibodies compared to Caucasian patients with anti-topo I. Pulmonary fibrosis was also more severe in the anti-U1 RNP-positive patients, but this was not associated with a difference in survival between African Americans and Caucasians. Anti-U3 RNP was associated with more severe gastrointestinal involvement in African Americans compared to Caucasians.

African Americans with SSc have more severe disease complications compared to Caucasians with SSc, and this is associated with both the type of autoantibody present and the severity of interstitial lung disease. Thus, it is hoped that early aggressive intervention in African Americans with interstitial lung disease will improve outcomes.