Prevalence of scleroderma spectrum disorders in the general population of South Carolina.

The prevalence of scleroderma spectrum disorders (including systemic sclerosis [SSc] meeting the American Rheumatism Association criteria and the less typical disorders meeting only our study criteria) was determined in a random sample of 6,998 subjects from the general population of South Carolina. The results suggest that the prevalence of these disorders may range from 67 to 265 per 100,000, which is 4.9 to 19.2 times higher than previously reported for definite SSc. The ratio of nondefinite cases to definite cases of SSc (those meeting American Rheumatism Association criteria) was 2.5. Most of the nondefinite cases were unrecognized prior to our study, which suggests the need for improved early diagnosis of scleroderma spectrum disorders. Brief histories of the 7 patients with scleroderma spectrum disorders whose cases formed the basis for our calculation of prevalence rates are included in this report.