Table 1.
Clinical characteristics of the study subjects.
| Healthy control group (n = 30) | All RA group (n = 77) | Low-activity RA group (n = 19) | Moderate-activity RA group (n = 29) | High-activity RA group (n = 29) | |
|---|---|---|---|---|---|
| Female (%) | 26 (86.7) | 66 (85.7) | 16 (84.2) | 25 (86.2) | 25 (86.2) |
| Age (years) | 51.6 ± 7.0 | 54.2 ± 8.8 | 51.2 ± 7.8 | 55.8 ± 8.5 | 54.4 ± 9.4 |
| Disease duration (years) | — | 5.0 (2-12) | 3.5 (2-13) | 7 (2.5-12.5) | 4 (1.5-10) |
| RF (kU/l)a | — | 65.1 (34.8-187) | 63.1 (37.9-146.8) | 62.1 (29.0-150) | 93.5 (34.6-259) |
| RF-positive (%)a | — | 62 (87.3) | 15 (93.8) | 24 (85.7) | 23 (85.2) |
| Anti-CCP (U/ml)b | — | 94.1 (31.7-532.3) | 87.1 (22.4-536.1) | 91.4 (49.2-501) | 100.9 (34.8-574) |
| Anti-CCP-positive (%)b | — | 67 (89.3) | 16 (88.9) | 26 (89.7) | 25 (89.3) |
| CRP (mg/l)c | — | 3.0 (0.9-9.9) | 1.3 (0.8-3.6) | 2.4 (0.9-9.3) | 5.1 (1.2-17.3) |
| CRP-positive (%)c | — | 20 (28.6) | 1 (6.7) | 8 (27.6) | 11 (42.3) |
| ESR (mm/h) | — | 27 (18-42) | 19 (11-26) | 33 (23-46) | 38 (21.5-51.5) |
| DAS28-ESR | — | 4.4 ± 1.6 | 2.6 ± 0.4 | 4.0 ± 1.0 | 5.9 ± 0.9 |
| Medicine use | — | ||||
| NSAIDs | — | 16 (20.8) | 2 (10.5) | 8 (27.6) | 6 (20.7) |
| DMARDs | — | 57 (74.0) | 17 (89.5) | 20 (69.0) | 20 (69.0) |
| Methotrexate | — | 47 (61.0) | 15 (78.9) | 15 (51.7) | 17 (58.6) |
| Leflunomide | — | 32 (41.6) | 10 (52.6) | 11 (37.9) | 11 (37.9) |
| Sulfasalazine | — | 8 (10.4) | 2 (10.5) | 5 (17.2) | 1 (3.4) |
| Prednisolone | — | 12 (15.6) | 2 (10.5) | 3 (10.3) | 7 (24.1) |
| Chinese medicine | — | 16 (20.8) | 4 (21.1) | 7 (24.1) | 7 (24.1) |
| No treatment | — | 7 (9.1) | 1 (5.3) | 2 (6.9) | 4 (13.8) |
| Otherd | — | 4 (5.2) | 1 (5.3) | 2 (6.9) | 1 (3.4) |
| Unknowne | — | 4 (5.2) | 0 (0) | 1 (3.4) | 3 (10.3) |
The data are expressed as n (%), mean ± standard deviation (SD), or median (interquartile range, 25th-75th). DAS28-ESR (Disease Activity Score of 28 joints using ESR), NSAIDs (nonsteroidal anti-inflammatory drugs), and DMARDs (disease-modifying antirheumatic drugs). aRF data were lacking in 6 subjects. Sixty-two out of 71 RA subjects were RF-positive. bAnti-CCP data were lacking in 2 subjects. Sixty-seven out of 75 RA subjects were anti-CCP-positive. cCRP data were lacking in 7 subjects. Twenty out of 70 RA subjects were CRP-positive. dThe patients defined as “other” included the following: those who were on their first visit to our hospital, were not on regular medication (one patient), and were taking other medicines that were not related to RA therapy (three patients). eThe patients defined as “unknown” included the following: those who were on their first visit to our hospital, could not tell which medication to use (two patients), and were only told of a few of their medicines (two patients).