Table 1. Characteristics of RA and SLE patients.
| Ro(+)La(−)RA | Ro(+)La(+)RA | Ro(−)La(−)RA | P [Ro(+)La(−) vs. Ro(−)La(−)] | P [Ro(+)La(+) vs. Ro(−)La(−)] | |
| Number | 181 | 40 | 704 | ||
| Mean age, years (SD) | 59.8 (13.1) | 59.6 (12.2) | 63.9 (11.8) | 0.0002* | 0.0390* |
| Male, n (%) | 15 (8.3) | 0 (0.0) | 143 (20.5) | 0.0001 | 0.0003 |
| Disease duration, years (SD) | 14.3 (10.3) | 17.7 (13.5) | 14.3 (10.9) | 0.9940* | 0.1017* |
| Steinbrocker stage III and IV, n (%) | 75 (51.0) | 18 (62.1) | 311 (57.4) | 0.1897 | 0.7019 |
| Association of secondary SS, n (%) | 34 (18.8) | 12 (30.0) | 26 (3.7) | 1.41×10−10 | 1.07×10−7 |
| Rheumatoid factor positive, n (%) | 146 (89.0) | 30 (88.2) | 545 (87.6) | 0.6878 | 1.0000 |
| ACPA positive, n (%) | 135 (87.1) | 30 (96.8) | 506 (91.8) | 0.0832 | 0.4999 |
| Ro(+)La(−)SLE | Ro(+)La(+)SLE | Ro(−)La(−)SLE | P [Ro(+)La(−) vs. Ro(−)La(−)] | P [Ro(+)La(+) vs. Ro(−)La(−)] | |
| Number | 129 | 45 | 137 | ||
| Mean age, years (SD) | 49.1 (15.3) | 46.0 (15.5) | 50.0 (14.7) | 0.7118* | 0.1676* |
| Male, n (%) | 11 (8.5) | 2 (4.4) | 15 (10.9) | 0.5417 | 0.2483 |
| Disease duration, years (SD) | 13.3 (12.1) | 7.2 (5.8) | 15.6 (12.1) | 0.1656* | 0.0001* |
| Association of secondary SS, n (%) | 6 (4.7) | 3 (6.7) | 1 (0.7) | 0.0598 | 0.0473 |
| Anti-dsDNA antibody positive, n (%) | 104 (80.6) | 31 (68.9) | 104 (75.9) | 0.3948 | 0.2720 |
SS: Sjögren’s syndrome, RA: rheumatoid arthritis, SLE: systemic lupus erythematosus, ACPA: anti-citrullinated peptide antibody, dsDNA: double-stranded-DNA, Ro(+)La(−): anti-Ro/SS-A-positive but anti-La/SS-B-negative, Ro(+)La(+): anti-Ro/SS-A- and anti-La/SS-B-positive, Ro(−)La(−): anti-Ro/SS-A- and anti-La/SS-B-negative. Association was tested by Fisher’s exact test using 2×2 contingency tables or Student’s t-test. *Student’s t-test was employed.