ABSTRACT
Rheumatoid Arthritis (RA) is an autoimmune chronic inammatory disease of unknown etiology (Aletaha et al. 2010). The prevalence of RA in adult population is approximately 0.5%–1%. It is observed in all ethnic groups (Alarcón 1995), with a female predominance, especially in patients between the fourth and sixth decades of life (Silman et al. 2002). In Brazil, a multicenter study also found prevalence of RA in adults ranging from 0.2% to 1.0% (Marques Neto et al. 1993).
