Rheumatoid Arthritis (RA)

Definition & epidemiology (Lancet 2016;388:2023)

  • Chronic, symmetric, debilitating, and destructive inflammatory polyarthritis characterized by proliferative synovial tissue (pannus) formation in affected joints
  • Pathogenesis involves over-production of TNF, IL-1, and IL-6 (∴ used as drug targets)
  • Risk stems from combination of genetic (~50% of risk), environmental influences (eg, smoking, silica dust), and Pt factors (periodontal disease, Δs in gut microbiome)
  • HLA-DRB1 haplotype a/w disease suscept., severity, & response to Rx (JAMA 2015;313:1645)
  • Prevalence = 1% adults and 5% of ♀ >70 y; ♀ to ♂ ratio = 3:1; peak incidence