Arthritis, Rheumatoid (RA)



Rheumatoid arthritis (RA) is a symmetric inflammatory disease primarily causing synovial inflammation and leading to the destruction of bone and cartilage.


Annual incidence: The United States is approximately 40 per 100,000 persons.


  • Prevalence: 0.24% of the general population worldwide; in the United States, the prevalence is between 0.5% and 1.0%.
  • Female:male, 2:1
  • The lifetime risk of developing RA: 3.6% in women and 1.7% in men

Etiology and Pathophysiology

RA is a chronic inflammatory disease. The end result is damage to cartilage and bone, potentially leading to significant disability. Multiple cytokines have been identified in the pathophysiology of RA. These include tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, and IL-17. Macrophages and osteoclast activation are also involved in the disease process, ultimately leading to bony erosion and degradation.

Estimated heritability 40%, >100 risk loci, HLA-DRB1 (the strongest genetic predisposition)

Risk Factors

Family history, genetic predisposition, middle-aged, female, lower socioeconomic status, cigarette smoking, infection, environmental, chronic inflammatory mucosal conditions

General Prevention

Smoking cessation, a well-balanced diet, achieving a healthy weight, regular physical activity, good dental hygiene

Commonly Associated Conditions

  • Interstitial lung disease
  • Pyoderma gangrenosum

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