It is very common to read in articles about systemic scleroderma that there are about 300,000 people in the US with this disease. This number is completely wrong, according to numerous research studies. The most complete data on the prevalence (number of diagnosed cases) and incidence (number of new cases per year) of systemic scleroderma comes from a 2003 Mayes study . This study estimates that the prevalence of systemic sclerosis (the medical term for systemic scleroderma) in the US is about 240 per million adults and the incidence of new cases each year is about 20 per million.
Based on 2013 US Census Bureau estimates of 242,470,820 adults in the US, this means that the number of diagnosed cases of systemic scleroderma is actually about 58,000 – a long way from the 300,000 figure that is commonly used!
To put this in perspective, depending on which study you look at, the prevalence of systemic lupus erythematosus (SLE) is about four times as high, close to 1000 per million adults in the US.
- Mayes MD. Scleroderma epidemiology. Rheum Dis Clin North Am. 2003;29(2):239-254. http://www.ncbi.nlm.nih.gov/pubmed/12841293.