Characterizing systemic sclerosis in Northern California: focus on Asian and Hispanic patients

Previous studies suggest that Asian and Hispanic patients with systemic sclerosis (SSc) may have more severe disease than their Caucasian counterparts. The purpose of this study is to compare the clinical features of a group of Asian, Hispanic, and Caucasian patients with SSc in Northern California.

We performed a cross-sectional study of patients receiving care at Stanford University Medical Center, Palo Alto Veterans Affairs Hospital, Santa Clara Valley Medical Center and San Francisco General Hospital between 1996 and 2006. Patients included in the analyses fulfilled the American College of Rheumatology criteria for SSc and could be classified as Caucasian, Asian, or Hispanic. Analyses using Caucasians as the reference group were performed.

One hundred and ninety-nine patients met the criteria for SSc, and 165 of these patients were classified as Caucasian (47%), Asian (26%), or Hispanic (27%). Disease subtype did not differ significantly among the three groups. Asian patients were less likely to have digital ulcers (26% vs. 47%, p=0.02) or anemia (26% vs. 45%, p=0.04) than Caucasians, and Hispanic patients had a lower frequency of lung disease than Caucasians (48% vs. 67%, p=0.04), but there were no other significant differences in disease manifestations.

In our cohort of SSc patients living in Northern California, clinical manifestations in Asian and Hispanic patients did not differ substantially from Caucasians. Further research is necessary to confirm these results and to investigate gene-environment interactions which may affect the clinical expression of disease in different racial groups.