Table 1.
Baseline characteristics of the study population and the factors found in PCA
| Component | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Baseline frequency | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| Age at inclusion (years, mean ± SD) | 59.2 (16.2) | 0.761 | ||||||||
| Female gender (n, %) | 219 (68.9) | 0.448 | 0.394 | |||||||
| Subacute onset of symptoms (versus insidious) | 188 (59.1) | 0.592 | -0.306 | 0.316 | ||||||
| Morning stiffness (min; mean ± SD) | 103.18 (112.0) | -0.496 | 0.484 | |||||||
| Fatigue (VAS; mean ± SD) | 45.1 (29.9) | -0.389 | 0.522 | |||||||
| Symptom duration (days; mean ± SD) | 172.1 (180.2) | 0.394 | -0.349 | 0.455 | ||||||
| Family history of RA (n, %) | 62 (19.5) | -0.326 | 0.594 | 0.380 | ||||||
| Past or present smoking (n, %) | 128 (40.3) | 0.652 | 0.375 | |||||||
| Fever (n, %) | 22 (6.9) | -0.319 | -0.426 | |||||||
| Involvement of small/large joints (n, %) | a | 0.604 | ||||||||
| Symmetry of involved joints (n, %) | 216 (67.9) | -0.379 | 0.308 | 0.331 | 0.370 | |||||
| Involvement of upper/lower extremities | b | 0.602 | -0.348 | |||||||
| Inflammatory back pain (n, %) | 16 (5.0) | 0.466 | 0.531 | 0,321 | ||||||
| Skin abnormalities (N, %)c | 56 (18.1) | 0.374 | ||||||||
| Swollen joint count (mean ± SD)d | 11.3 (8.5) | 0.445 | 0.365 | |||||||
| CRP (mg/L; mean ± SD) | 30.10 (34.4) | 0.315 | 0.434 | 0.512 | ||||||
| RF (IU/ml) (mean ± SD)e | 7.12 (19.5) | 0.305 | -0.345 | 0.315 | -0.602 | |||||
| MCV positivity (n, %) | 59 (18.6) | 0.470 | 0.376 | -0.321 | ||||||
| Erosive disease at baseline (n, %) | 202 (63.5) | 0.642 | 0.332 | |||||||
| Explained variance per component (%) | 10.0 | 8.6 | 8.0 | 7.4 | 6.8 | 6.5 | 5.6 | 5.5 | 5.4 | |
Involvement of upper extremities: shoulder, elbow, wrist, or hand joints; involvement of lower extremities: joints of hip, knee, ankle, feet or toe joints.aInvolvement of small/large joints: in 163 patients (51.3%), only small joints of hands and feet were involved. In 53 patients (16.7%) only large joints were involved. In 93 patients (29.2%), both small and large joints were involved.aInvolvement of upper/lower extremities: in 156 patients (49.1%) only joints in the upper extremities were involved. In 28 patients (8.8%), only joints in the lower extremities were involved. In 96 (30.2%) patients, joints in both lower and upper extremities were involved.cSkin abnormalities: absence or presence of dermatological abnormalities such as psoriatic lesions, ulcers, rheumatoid nodules and so on.dSwollen Joint Count: 44-Swollen Joint Count.eAnalyses were performed on RF in groups (less than reference value, 1 to 3 times reference value, or more than 3 times reference value). CRP, C-reactive protein; MCV, mutated citrullinated vimentin; RF, rheumatoid factor; VAS, visual analogue scale.