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Table 1 Baseline characteristics of the study population and the factors found in PCA

From: Can anti-cyclic citrullinated peptide antibody-negative RA be subdivided into clinical subphenotypes?

   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
  1. 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.