SAT0608 THE PREVALENCE OF RHEUMATOID ARTHRITIS IN CHILE, A STUDY PERFORMED AS PART OF THE NATIONAL SURVEY HEALTH (ENS 2016-17)
Authors: josefina duran, Loreto Massardo, Carolina Llanos, Sergio Iacobelli, Paula Burgos, Raquel Aguilera, Maria Eugenia Martinez, Marcela Cisternas, Macarena Armstrong, Mirentxu Iruretagoyena, Francisco Radrigan, Alvaro Passi, Pablo Riedemann, Camila Cifuentes, Lucero Hagedorn, Natalia Crisostomo, Alvaro Cisternas, Paula Margozzini
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Genetic and environmental backgrounds influence the development of rheumatoid arthritis (RA) and its frequency has regional variations. In Latin America epidemiologic data are scarce. <h3>Objectives:</h3> We aimed to determine the prevalence of RA in Chile as part of the National Health Survey (ENS, Encuesta Nacional de Salud). <h3>Methods:</h3> ENS was a cross-sectional household survey with a stratified multistage probability sample of 6,233 participants performed between August 2016 and March 2017. A screening instrument for RA was applied to a random sample of 3,700 subjects &gt;30 years old.<sup>1, 2</sup> Positive screening was defined by at least one of the following: (i) 2 swollen joints for at least 4 consecutive weeks (past or present) and/or (ii) a diagnosis of arthritis in the past. Individuals with positive screening had Rheumatoid Factor, Anti-citrullinated protein antibodies, and C-reactive protein measured and clinical examination was performed by a rheumatologist. Self-report of doctor-diagnosed RA was also performed. <h3>Results:</h3> The screening questionnaire was applied to 2,998 subjects. Seven hundred and thirty-eight (22.1%) had a positive screening. Among the subjects with a positive screening 493 (66%) had consulted a rheumatologist. Thirty-one subjects had RA according to the ACR/EULAR 2010 classification criteria, which corresponds to 0.6% (95%CI 0.3, 1.2). Three point three per cent reported having RA. Prevalence was higher in women and in high SES. <h3>Conclusion:</h3> According to this national population-based study RA prevalence in Chile is 0.6% (0.3, 1.2). This is similar to the prevalence previously reported in developed countries, which is noteworthy given the differences in sociodemographic characteristics which exist compared to Chile. Self-reporting leads to an important overestimation of RA. Our study suggests there is a higher risk of RA in subjects with high SES in this region. <h3>References</h3> [1] MacGregor AJ, Riste LK, Hazes JMW, Silman AJ. Low prevalence of rheumatoid arthritis in Black Caribbeans compared with Whites in inner city Manchester. Ann Rheum Dis 1994;53:293–7 [2] Carmona L, et al. The prevalence of rheumatoid arthritis in the general population of Spain. Rheumatology (Oxford). 2002;41(1):88-95. <h3>Disclosure of Interests:</h3> josefina duran: None declared, loreto massardo Speakers bureau: Werfen, carolina llanos: None declared, sergio iacobelli: None declared, Paula Burgos: None declared, Raquel Aguilera: None declared, maria eugenia martinez: None declared, marcela cisternas: None declared, macarena armstrong: None declared, mirentxu iruretagoyena: None declared, francisco radrigan: None declared, alvaro passi: None declared, pablo riedemann: None declared, camila cifuentes: None declared, lucero hagedorn: None declared, natalia crisostomo: None declared, alvaro cisternas: None declared, paula margozzini: None declared