Incidence and prevalence of Polymyalgia Rheumatica and Giant Cell Arteritis in a Health Care Management Organization in Buenos Aires, Argentina

Objective To estimate incidence and prevalence of PMR and GCA in a university hospital–based health management organization (HIMCP) in Argentina. Methods Overall, and sex-specific incidence rates and prevalence were calculated (age ≥ 50 years). Incidence study followed members with continuous affiliation ≥ 1 year from January 2000 to December 2015. Diagnosis as per the 2012 EULAR/ACR criteria for PMR or the ACR 1990 criteria for GCA. Prevalence was calculated on January 1, 2015. Results 176,558 persons contributed a total of 1,046,620 person-years. 825 developed PMR; incidence rate (IR) (per 100,000 person-years) of 78.8 (95% CI 73.4–84.2) overall; 90.1 (95% CI 82.9–97.2) for women, 58.9 (95% CI 51.1–66.6) for men. Ninety persons developed GCA; IR of 8.6 (95%-CI 6.8–10.4) overall; 11.1 (95%-CI 8.5–10.6) for women, 4.2 (2.2–6.3) for men. Prevalent PMR cases: 205 and prevalent GCA cases: 23 were identified from a population of 80,335. Prevalence (Pr) of PMR was 255 per 100,000 (95% CI 220–290) overall, 280 (95% CI 234–325) for women, 209 (95% CI 150–262) for men, and Pr of GCA was 28.6 per 100,000 (95% CI 16.9–40.3) overall, 36.4 (95% CI 20.1– 52.8) for women, 14.2 (95% CI 0.3–28.1) for men Conclusion This is the first study of incidence and prevalence of PMR and GCA in Argentina. There were similarities and differences with series from other parts of the world, but population based epidemiologic studies in Latin America are needed.