Patient characteristics at baseline and during 3 years of followup, by anticitrullinated protein antibody (ACPA) status. Time-averaged SJC, ESR, and DAS measured during 3-year followup. Data are mean (SD), median (25th–75th percentile), or percentage (number).
| Characteristic | ACPA-negative n = 87 | ACPA-positive, n = 180 | p* |
|---|---|---|---|
| Age at diagnosis, yrs | 60 (14) | 54 (12) | 0.001 |
| Female, % (n) | 67 (58) | 60 (107) | 0.255 |
| IgM RF-positive, % (n) | 44 (38) | 93 (167) | < 0.001 |
| No. visits | 10 (8–14) | 11 (8–22) | 0.297 |
| Baseline SJC | 14 (10–23) | 14 (10–20) | 0.317 |
| Baseline ESR | 22 (9–45) | 38 (15–56) | 0.005 |
| Baseline DAS | 3.9 (1.3) | 4.0 (1.2) | 0.580 |
| Baseline tender joint count | 14 (6–21) | 12 (6–19) | 0.882 |
| Baseline VAS GH | 48 (25) | 45 (24) | 0.386 |
| Time-averaged SJC | 9 (5–11) | 9 (6–12) | 0.137 |
| Time-averaged ESR | 14 (8–25) | 19 (10–29) | 0.042 |
| Time-averaged DAS | 2.6 (0.9) | 2.9 (0.9) | 0.041 |
| Ratingen score at baseline | 0 (0–1) | 1 (0–3) | 0.001 |
| Ratingen score at 3 yrs | 1 (0–8) | 9 (3–19) | < 0.001 |
| Change in Ratingen, 0–3 years | 0 (0–6) | 7 (2–16) | < 0.001 |
| Newly damaged joints, 0–3 years, % (n) | 48 (42) | 82 (148) | < 0.001 |
| DMARD, % (n) | |||
| Combination therapy | 76 (66) | 75 (135) | 0.056 |
| Monotherapy | 14 (12) | 21 (38) | |
| None | 12 (9) | 4 (7) | |
| Methotrexate use, % (n) | 41 (36) | 38 (69) | 0.351 |
| Corticosteroids, % (n) | |||
| Total | 56 (49) | 61 (110) | 0.455 |
| Oral < 15 mg | 9 (8) | 15 (27) | 0.048 |
| Oral ≥ 15 mg | 13 (11) | 5 (9) |
↵* Independent t test, Mann-Whitney U test, and chi-square test, as appropriate. RF: rheumatoid factor; SJC: swollen joint count 44 joints; DAS: Disease Activity Score; ESR: erythrocyte sedimentation rate; TJC: tender joint count 53 joints; VAS GH: general health scored on a visual analog scale; DMARD: disease-modifying antirheumatic drug.