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

Abstract

Objective Epidemiology studies suggest that Systemic Sclerosis 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 two ethnic subgroups. This study examines the demographic and disease features, frequency and severity of internal organ system involvement and survival in African-American and Caucasian SSc patients with particular attention to their serum autoantibody profiles. Methods Demographic, clinical, autoantibody, natural history of organ involvement and survival were studied in consecutive African-American and Caucasian patients seen between 1972 and 2007 as part of the Pittsburgh Scleroderma Database. The Medsger Disease Severity Scale was used to determine severe disease. Results African-American patients were more likely to have anti topoisomerase, anti U1RNP and U3 RNP auto-antibodies. Comparing African-American and Caucasians with these antibodies, African-American patients with anti topoisomerase antibody had more frequent and more severe pulmonary fibrosis than Caucasians and an associated decreased survival. Pulmonary fibrosis was also more severe in the U1 RNP patients but 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-American’s compared to Caucasians. Conclusions African Americans with systemic sclerosis have more severe disease complications than Caucasians both because of the type of autoantibody they have and because they have more severe interstitial lung disease even within the antibody subset. Early aggressive intervention in all African Americans with interstitial lung disease should be a priority.

Interstitial lung disease in South Africans with systemic sclerosis

“…In addition, McNearney et al, (37) reported that African American patients have a higher rate of ILD (46%) compared to White (19%) and Hispanic (25%) patients, as well as a more severe ILD as measured by pulmonary function tests (PFTs). Steen and colleagues (6) also reported a higher rate of ILD amongst African American patients (52%) compared to White patients (11%), particularly those that were ATA positive (44% in African American SSc patients versus 18%…”

“…A more severe organ involvement is seen in those with dcSSc, compared to those with lcSSc. In Caucasian dominant populations such as in Europe and North America lcSSc is more common (56%) than dcSSc (34%) (5) , whereas in AfricanAmerican and Black populations the reverse is true, with rates of dcSSc of up to 82% being reported in Nigeria (6)(7)(8)(9) .…”

“…However, the ethnicity of the patients at CHBAH was exclusively Black, and world-wide African American patients with SSc are reported to present at a younger age and with more severe disease (2,6,18,19) .…”

“…Anti-topoisomerase I antibody itself seems to be associated with dcSSc (occurs in 40%) as well as interstitial lung disease (ILD) (occurs in 45%), and confers a more severe disease process (6) . Anti-centromere antibody is more common in Caucasian patients (25% versus 7% in African Americans) (6) , and in those patients with lcSSc (40-60%) (6,29,30) .…”

“…American patients have a more severe ILD (32% severe ILD in African American patients versus 13% severe ILD in Caucasian patients) (6) with a higher mortality rate compared to matched Caucasian patients (6,32,50) . In fact, the hazard ratio of 1.68…”