To estimate incidence and prevalence rates of rheumatoid arthritis (RA) in the city of Buenos Aires (CABA), Argentina, using data from a university hospital-based health management organization.
Global, age-specific, and sex-specific incidence and prevalence rates were calculated for members of the Hospital Italiano Medical Care Program (HIMCP), age ≥ 18 years. Incidence study followed members with continuous affiliation ≥ 1 year from January 2000 to January 2015 until he/she voluntarily left the HIMCP, RA was diagnosed, death, or study finalization. Cases from the Rheumatology Section database, electronic medical records, laboratory database, and pharmacy database were filtered with the 2010 American College of Rheumatology/European League Against Rheumatism criteria. Prevalence was calculated on January 1, 2015, and standardized for CABA. Capture-recapture (C-RC) analysis estimated true population sizes.
In the study period, incidence rates (cases per 100,000 person-yrs) were 18.5 (95% CI 16.7-20.4) overall, 25.2 (95% CI 22.4-28.0) for women, and 8.8 (95% CI 6.8-10.8) for men. Prevalence rates (percentage of RA cases in the sample population) were 0.329 (95% CI 0.298-0.359) overall, 0.464 (95% CI 0.417-0.510) for women, and 0.123 (95% CI 0.093-0.152) for men. Standardized CABA prevalence rate was 0.300 (95% CI 0.292-0.307). C-RC adjusted rates were almost the same as unadjusted rates.
This study's incidence and prevalence rates are in the lower range of the rates found around the world. Our female to male prevalence ratio was 4:1. Our peak incidence age was in the sixth and seventh decades for both sexes.