Table 1.
Baseline characteristics of the patients with Clinically Suspect Arthralgia (N = 507)
| Patient characteristic | ||
| Age in years, mean (SD) | 44 | (13) |
| Female sex, n (%) | 390 | (77) |
| Family history of RA, n (%) | 147 | (29) |
| Symptom duration in weeks, median (IQR) | 17 | (9–32) |
| Presence of morning stiffness ≥60 min, n (%) | 182 | (36) |
| Current smoker, n (%) | 137 | (27) |
| 68-TJC, median (IQR) | 6 | (3–10) |
| Increased CRP (≥5 mg/L), n (%) | 106 | (21) |
| Presence of local subclinical joint inflammation, n (%) | 255 | (50) |
| Positive for EULAR definition for arthralgia suspicious for progression to RA [17], n (%) | 325 | (64) |
| Autoantibody status | ||
| Negative for IgM-RF and ACPA, n (%) | 385 | (76) |
| IgM-RF-positive (≥3.5 IU/mL), ACPA-negative, n (%) | 52 | (10) |
| ACPA-positive (≥7 U/mL), IgM-RF-negative, n (%) | 15 | (3) |
| IgM-RF-positive and ACPA-positive, n (%) | 55 | (11) |
| ACPA-level (U/ml) in ACPA-positive patients, median (IQR) | 162 | (35–340) |
| ACPA-level (U/ml) in ACPA-positive patients without local joint inflammation, median (IQR) | 129 | (23–340) |
| ACPA-level (U/ml) in ACPA-positive patients with local joint inflammation, median (IQR) | 191 | (38–340) |
Local subclinical joint inflammation was identified if the prevalence of magnetic resonance imaging (MRI)-detected bone marrow edema, synovitis or tenosynovitis was higher than that of age-matched symptom-free controls
ACPA anti-citrullinated peptide antibody, CRP C-reactive protein, EULAR European League Against Rheumatism, IgM-RF immunoglobulin M rheumatoid factor, IQR interquartile range, RA rheumatoid arthritis, RF rheumatoid factor, SD standard deviation, TJC tender joint count