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.

De Rooy et al. Arthritis Research & Therapy 2011 13:R180   doi:10.1186/ar3505

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