Baseline characteristics of seronegative subjects meeting RA criteria compared to those not meeting criteria. Meeting criteria for RA was defined as meeting either the 1987 ACR RA criteria or the 2010 ACR/EULAR RA criteria. Values are n (%) unless otherwise specified.
| Characteristics | Seronegative Patients Meeting RA Criteria, n = 179 | n | Seronegative Patients Not Meeting RA Criteria, n = 37 | n | p |
|---|---|---|---|---|---|
| Age, yrs, mean (SD) | 58 (14) | 179 | 53 (15) | 37 | 0.1082 |
| Male | 53 (30) | 179 | 14 (38) | 37 | 0.3343 |
| Symptom duration, days, mean (SD) | 161 (83) | 179 | 196 (102) | 37 | 0.0245 |
| Ever smoker | 92 (52) | 178 | 19 (52) | 37 | 1 |
| SJC28, mean (SD) | 9.7 (6.7) | 179 | 3.4 (4.3) | 32 | < 0.0001 |
| TJC28, mean (SD) | 10.4 (7.1) | 179 | 3.1 (3.5) | 32 | < 0.0001 |
| ESR, mean (SD) | 26.3 (22.9) | 174 | 18.6 (16.0) | 37 | 0.0176 |
| CRP, mg/l, mean (SD) | 15.3 (19.6) | 168 | 7.0 (6.8) | 37 | 0.0119 |
| Erosions | 53 (34) | 155 | 5 (19) | 26 | 0.1737 |
| DAS28, mean (SD) | 5.2 (1.6) | 171 | 3.6 (1.4) | 32 | < 0.0001 |
| HAQ, mean (SD) | 0.67 (0.66) | 164 | 0.53 (0.56) | 35 | 0.2358 |
| DMARD | 154 (87) | 177 | 24 (80) | 30 | 0.3904 |
| Biologics | 4 (3) | 177 | 1 (3) | 30 | 0.5467 |
| Corticosteroids | 102 (58) | 177 | 18 (60) | 30 | 0.8442 |
RA: rheumatoid arthritis; ACR: American College of Rheumatology; EULAR: European League Against Rheumatism; SJC28: swollen joint count of 28 joints; TJC28: tender joint count of 28 joints; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; DAS28: 28-joint Disease Activity Score; HAQ: Health Assessment Questionnaire; DMARD: disease-modifying antirheumatic drug.