What is Arthritis?
Arthritis is a group of approximately 100 conditions characterized by inflammation of the joints, causing pain, swelling, stiffness, and potential disability. 1
Types and Prevalence
- Rheumatoid arthritis (RA) is the most common autoimmune form of arthritis, affecting approximately 1% of the global population, with higher prevalence in people of European or Asian ancestry 2
- In the United States, arthritis affects an estimated 53.2 million adults (21.2% of the population), with higher prevalence among women (20.9%) than men (16.3%) 1
- The prevalence increases considerably with age, affecting approximately 6% of the white population older than 65 years 2
- Lifetime risk of developing rheumatoid arthritis is 3.6% in women and 1.7% in men in the United States 2
Clinical Manifestations
- Joint swelling not caused by trauma, particularly involving at least two joints, is the hallmark sign of inflammatory arthritis 3
- Morning stiffness lasting at least 1 hour before maximal improvement is a typical and distinctive sign of rheumatoid arthritis 4
- Symmetric involvement of small joints, particularly metacarpophalangeal, proximal interphalangeal, and metatarsophalangeal joints is characteristic of RA 3
- Pain with joint swelling, especially of the hands and feet, though any appendicular joint may become involved 2
- Subcutaneous nodules and extra-articular manifestations (interstitial lung disease, vasculitis, inflammatory eye disease) may occur in severe cases 2
Distinguishing Features from Other Arthritic Conditions
- Morning stiffness in rheumatoid arthritis typically lasts 1 hour or more, while in osteoarthritis it is usually mild and brief, lasting less than 30 minutes 4
- RA involves symmetric joint distribution, whereas osteoarthritis stiffness affects specific joints rather than being symmetrically distributed 4
- RA involves persistent systemic inflammation, while osteoarthritis is primarily characterized by cartilage degradation with limited inflammatory component 4
Diagnosis
- Laboratory markers include elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) 3
- Presence of rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (anti-CCP) may be detected early and are predictive of persistent disease 3
- In doubtful cases, ultrasound, power Doppler, and MRI may help detect early synovitis 3
- Plain film radiography is standard for assessing anatomic changes, with early features including soft tissue swelling and mild juxtaarticular osteoporosis 5
Impact on Health and Quality of Life
- Arthritis is a leading cause of activity limitations, disability, and chronic pain 1
- More than one-third of patients eventually experience work disability due to the disease 2
- Life expectancy can be shortened by 3-5 years, especially in patients with extra-articular disease 2
- High prevalence among adults with other chronic conditions: COPD (57.6%), dementia (55.9%), stroke (52.6%), heart disease (51.5%), diabetes (43.1%), and cancer (43.1%) 1
Importance of Early Recognition
- Patients with arthritis affecting more than one joint should be referred to a rheumatologist, ideally within six weeks of symptom onset 3
- Early diagnosis allows for earlier treatment with disease-modifying antirheumatic drugs (DMARDs), which is associated with better outcomes 3
- Even if patients don't yet fulfill established classification criteria for rheumatoid arthritis, those at risk of developing persistent disease should be started with DMARDs as early as possible 3