From the Guidelines
The cut-offs for diagnosing rheumatoid arthritis (RA) are based on a scoring system that considers joint involvement, serology, acute-phase reactants, and duration of symptoms, with a score of 6 or higher out of 10 indicating definite RA.
Key Considerations
- The scoring system assesses the number and size of involved joints (0-5 points), with 1 large joint scoring 0 points, 2-10 large joints scoring 1 point, and small joint involvement scoring 2-5 points, as outlined in the 2010 ACR/EULAR Classification Criteria for Rheumatoid Arthritis 1.
- Serologic findings, including rheumatoid factor and anti-citrullinated protein antibody levels, are also considered, with negative results scoring 0 points, low positive results scoring 2 points, and high positive results scoring 3 points 1.
- Acute-phase reactants, such as C-reactive protein and erythrocyte sedimentation rate, are assessed, with normal results scoring 0 points and abnormal results scoring 1 point 1.
- Duration of symptoms is also a factor, with symptoms lasting less than 6 weeks scoring 0 points and symptoms lasting 6 weeks or longer scoring 1 point 1.
Clinical Application
- These criteria are primarily used for classification in research settings, but they can guide clinical diagnosis as well 1.
- A rheumatologist should be consulted for a definitive diagnosis, as they will consider these criteria along with the patient's overall clinical presentation and other potential causes of joint inflammation.
- It's essential to note that patients with a score of less than 6 can still be reassessed over time, and their status may change as more information becomes available 1.
From the Research
Rheumatoid Arthritis (RA) Cut-offs
- The cut-offs for Rheumatoid Arthritis (RA) are not explicitly stated in the provided studies, but several studies discuss the diagnosis and treatment of RA 2, 3, 4, 5, 6.
- According to the study published in 2011, the diagnosis of RA combines the patient history of joint pain and stiffness and the physical examination documentation of symmetric polyarticular joint swelling (synovitis) 4.
- Laboratory tests, including radiographs and blood tests for biomarkers such as rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP), can provide useful information to confirm the diagnosis of RA 4, 5.
- The American College of Rheumatology and European Alliance of Associations for Rheumatology recommend a treat-to-target approach, including rapid interventions to reduce disease activity and achieve remission 5.
- Monitoring and assessment instruments for RA include the Disease Activity Score 28 (DAS28), the Simplified Disease Activity Index (SDAI), and the Clinical Disease Activity Index (CDAI) 4.
- A study published in 2010 discusses the limitations of the 1987 RA criteria and the need for new criteria that can facilitate early diagnosis and encourage initiation of therapy through disease modifying drugs (DMARDs) 6.
- The study published in 2021 discusses the use of a multiple biomarker approach for the diagnosis and therapy of RA, but does not provide specific cut-offs for RA diagnosis 3.
- The study published in 2018 discusses the treatment target for RA, which is remission or a state of at least low disease activity, and should be attained within 6 months 2.