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Leiden Clinical Prediction Rule for Undifferentiated Arthritis
Estimates 1-year risk of progression to rheumatoid arthritis in recent-onset undifferentiated arthritis.
Leiden Clinical Prediction Rule for Undifferentiated Arthritis
Age
years
Sex
Symptom localization
Symmetric joint distribution
Morning stiffness intensity (0-100 mm VAS)
Tender joint count
joints
Swollen joint count
joints
CRP
mg/L
Rheumatoid factor positive
Anti-CCP (ACPA) positive
Complete the fields above to see the result.
When to use
- Estimating 1-year probability of progression to rheumatoid arthritis in patients with recent-onset undifferentiated arthritis, to guide early DMARD decisions.
Formula
Weighted sum of age (x0.02/yr), female sex (1), symptom localization (0-1.5), symmetry (0.5), morning stiffness intensity (0-2), tender/swollen joint counts (0-1 each), CRP (0-1.5), RF positive (1), ACPA positive (2). Range 0-14; <6 low risk, 6 to <8 indeterminate, >=8 high risk.
Pearls and pitfalls
- Scores from 6 up to (but not including) 8 fall in an indeterminate zone — the original derivation could not reliably classify these patients.
- ACPA carries twice the weight of RF, reflecting its stronger association with progression to RA.