Proportions of patients in the mono, oligo, and polyarticular groups fulfilling the individual criteria, and score results of the prediction rule for RA development22.
| Variable | Points | Mono (n = 243) | Oligo (n = 216) | Poly (n = 175) | p |
|---|---|---|---|---|---|
| Female sex | 1 | 52.7 | 56.9 | 57.7 | 0.49 |
| Small joints | 0.5 | 14.8 | 42.1 | 93.1 | < 0.001 |
| Symmetrical arthritis | 0.5 | NA | 54.6 | 90.9 | NA |
| Arthritis in upper extremities | 1 | 23.5 | 46.8 | 90.9 | < 0.001 |
| Arthritis in upper and lower extremities | 1.5 | NA | 25.9 | 64.6 | < 0.001 |
| Morning stiffness 30–59 min | 0.5 | 16.5 | 18.1 | 17.7 | 0.68 |
| Morning stiffness ≥ 60 min | 1 | 38.7 | 53.7 | 65.7 | 0.006 |
| TJC 4–10 | 0.5 | 2.1 | 15.3 | 42.9 | NA |
| TJC ≥ 11 | 1 | 0.4 | 17.6 | 63.4 | NA |
| SJC 4–10 | 0.5 | NA | 17.6 | 63.4 | NA |
| SJC ≥ 11 | 1 | NA | NA | 100 | NA |
| CRP 5–50 | 0.5 | 57.0 | 53.7 | 55.2 | 0.77 |
| CRP ≥ 51 | 1.5 | 14.0 | 23.1 | 28.7 | 0.001 |
| Rheumatoid factor positivity | 1 | 4.3 | 4.7 | 29.9 | < 0.001 |
| Anti-CCP positivity | 2 | 4.7 | 7.5 | 37.2 | < 0.001 |
| Prediction rule scores | |||||
| Total score, mean (range) | 2.87 (0.49–6.82) | 3.97 (1.00–7.50) | 6.85 (2.74–11.19) | ||
| Score ≤ 6 (low) | 99.6 | 91.7 | 31.4 | ||
| Score > 6 and < 8 (intermediate) | 0.4 | 8.3 | 42.3 | ||
| Score ≥ 8 (high) | 0.0 | 0.0 | 26.3 | ||
Values are percentages if not stated otherwise. NA: not applicable; TJC: tender joint count; SJC: swollen joint count; CRP: C-reactive protein; CCP: cyclic citrullinated peptide.