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Secular Trends in the Incidence, Prevalence of RA

Rheumatol Int; ePub 2019 Jan 17; Kawatkar, et al

During the past 2 decades, while the incidence of rheumatoid arthritis (RA) was unchanged, the prevalence had increased significantly overall, as well as within every subgroup of race, ethnicity, and sex. This according to a recent study that sought to estimate secular trends in the overall incidence rate (IR) and prevalence rate (PR) of RA and subgroup-specific IR and PR by race, ethnicity, and sex in a multi-ethnic population. The study was conducted within the adult population of Kaiser Permanente Southern California health plan. From January 1995 up to and including December 2014, annual IR and PR were calculated separately by race, ethnicity, sex, and pooled overall. Investigators found:

  • Average overall IR was 53 per 100,000 person-years.
  • The overall as well as subgroup-specific annual IR of RA were unchanged from 1995 to 2014.
  • In 1995, the overall PR of RA was 59 per 100,000 person-years which increased by 14% annually thereafter.
  • The increase in PR in Caucasians was lower as compared to African American, Asian, and other races (13% vs 15%, 15%, and 18%, respectively).
  • Compared to non-Hispanic ethnicity, the increase in PR among Hispanics was higher (17% vs 14%).


Kawatkar AA, Gabriel SE, Jacobsen SJ. Secular trends in the incidence and prevalence of rheumatoid arthritis within members of an integrated health care delivery system. [Published online ahead of print January 17, 2019]. Rheumatol Int. doi:10.1007/s00296-018-04235-y.