The Prevalence of Rheumatoid Arthritis: A Systematic Review of Population-based Studies.

The literature reports a wide range of point and period prevalence based on population and method of data collection, but average point and period prevalence of RA were 51 in 10,000 and 56 in 10,000, respectively. Higher urban vs rural prevalence may be biased due to poor case findings in areas with less healthcare or differences in risk environment. The population database studies were more consistent than sampling studies, and linked databases in different continents appeared to provide a consistent estimate of RA period prevalence, confirming the high value of rheumatologist diagnosis as classification criteria.