Table 1.
Baseline characteristics of the participants before and after propensity-score matching.
| Variables | Before Matching (n= 2837) | After Matching* (n= 1196) | |||||
|---|---|---|---|---|---|---|---|
| Non-RA (n = 1662) | RA (n = 1175) | P value | Non-RA (n = 598) | RA (n = 598) | P value | ||
| Age (years) | 38.9 (14.4) | 57.4 (13.1) | <0.001 | 51.1 (15.0) | 51.4 (13.7) | 0.688 | |
| Sex | <0.001 | 0.067 | |||||
| Male | 749 (45.07%) | 335 (28.51%) | 252 (42.14%) | 221 (36.96%) | |||
| Female | 913 (54.93%) | 840 (71.49%) | 346 (57.86%) | 377 (63.04%) | |||
| CCP (U/mL) | 0.5 (0.5-1.8) | 198.6 (23.1-200.0) | <0.001 | 0.5 (0.5-2.1) | 192.9 (21.1-215.5) | <0.001 | |
| MCV (U/mL) | 6.3 (4.4-8.3) | 255.5 (25.3-1000.0) | <0.001 | 6.2 (4.5-8.6) | 174.7 (21.3-1000.0) | <0.001 | |
| RF (IU/mL) | 9.7 (8.9-10.8) | 99.2 (15.0-368.5) | <0.001 | 9.7 (8.9-10.9) | 94.8 (13.4-341.5) | <0.001 | |
| CRP (mg/L) | 15.1 (4.7-38.2) | 19.7 (6.2-53.6) | <0.001 | 15.4 (4.1-41.7) | 19.2 (5.3-46.9) | 0.06 | |
| ESR (mm/hour) | 13.0 (6.0-26.0) | 50.0 (26.0-78.0) | <0.001 | 18.0 (8.0-51.0) | 45.0 (23.0-73.0) | <0.001 | |
| ANA titers | <0.001 | <0.001 | |||||
| Negative | 1119 (67.33%) | 289 (24.60%) | 370 (61.87%) | 133 (22.24%) | |||
| 1:100 | 502 (30.20%) | 534 (45.45%) | 198 (33.11%) | 281 (46.99%) | |||
| 1:320 | 25 (1.50%) | 197 (16.77%) | 16 (2.68%) | 96 (16.05%) | |||
| 1:1000 | 16 (0.96%) | 155 (13.19%) | 14 (2.34%) | 88 (14.72%) | |||
| ANA patterns | <0.001 | <0.001 | |||||
| Negative | 1119 (67.33%) | 289 (24.60%) | 370 (61.87%) | 133 (22.24%) | |||
| Nuclear homogeneous | 76 (4.57%) | 479 (40.77%) | 42 (7.02%) | 255 (42.64%) | |||
| Nuclear speckled | 332 (19.98%) | 282 (24.00%) | 127 (21.24%) | 156 (26.09%) | |||
| Centromere | 4 (0.24%) | 9 (0.77%) | 2 (0.33%) | 3 (0.50%) | |||
| Nucleolar | 54 (3.25%) | 31 (2.64%) | 24 (4.01%) | 14 (2.34%) | |||
| Cytoplasmic speckled | 51 (3.07%) | 70 (5.96%) | 27 (4.52%) | 30 (5.02%) | |||
| Other patterns | 26 (1.56%) | 15 (1.28%) | 6 (1.00%) | 7 (1.17%) | |||
*Age and sex were matched between RA and Non-RA groups.
Abbreviations: RA, rheumatoid arthritis; ANA, antinuclear antibody; CCP, cyclic citrullinated peptide; MCV, mutant citrulline vimentin; RF, rheumatoid factor; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate.