Demographic and clinical characteristics at baseline stratified by antidrug antibody status
| Baseline characteristics | Total patient population (n=112) | Patients with antidrug antibodies detected (n=42) | Patients without antidrug antibodies detected (n=70) | p Value |
|---|---|---|---|---|
| Age years, mean (SD) | 58.0±12 | 57.3±13 | 58.5±12 | 0.30 |
| Female (%) | 78 (69.6) | 27 (64.3) | 51 (72.9) | 0.30 |
| BMI (IQR) | 27.1 (23.4–32.0) | 26.6 (23.5–30.9) | 27.9 (23.0–33.6) | 0.54 |
| Disease status | ||||
| Disease duration, median (IQR), years | 7.0 (3.3–14.4) | 8.3 (5.7–15.3) | 6.0 (3.3–12.4) | 0.095 |
| RF positivity* (%) | 61 (73.4) | 23 (76.7) | 38 (71.7) | 0.62 |
| Erosive disease, n*(%) | 34 (48.6) | 14 (56.0) | 20 (44.4) | 0.35 |
| DAS28, mean (SD) | 5.9 (0.8) | 6.0 (0.9) | 5.9 (0.8) | 0.26 |
| Tender joint count (28 joints), median (IQR) | 17 (10–24) | 17 (10–24) | 17 (11–23) | 0.84 |
| Swollen joint count (28 joints), median (IQR) | 9 (6–13) | 10 (7–16) | 8 (6–12) | 0.043 |
| ESR, median (IQR), mm/h | 18 (10.0–37.0) | 23.0 (12.0–54.0) | 16.5 (10.0–31.0) | 0.24 |
| C-reactive protein, median (IQR), mg/L | 7.5 (3.3–21.0) | 8.9 (3.8–24.0) | 7.2 (3.22–20.0) | 0.57 |
| Patient global score | 75 (56–85) | 80 (70–86) | 75 (54–82.5) | 0.25 |
| Prior biologic (%) | 9 (8.0) | 6 (14.3) | 3 (4.3) | 0.059 |
| Oral steroids at baseline (%)* | 21 (18.7) | 5 (18.5) | 16 (19.2) | 0.68 |
| nbDMARD therapy | ||||
| Methotrexate use (%) | 60 (53.5) | 22 (52.4) | 38 (54.3) | 0.85 |
| Methotrexate dose, median (IQR) mg/week | 20 (15–25) | 20 (15–25) | 20 (15–25) | 0.87 |
| Sulfasalazine (%) | 17 (15.2) | 6 (14.3) | 11 (15.7) | 0.84 |
| Sulfasalazine Median (IQR) mg/day | 1000 (1000–1000) | 1000 (1000–1000) | 1000 (1000–1000) | 0.75 |
| Leflunomide n (%) | 3 (2.7) | 1 (2.4) | 2 (2.9) | 0.88 |
| Hydroxychloroquine (%) | 6 (5.3) | 2 (4.8) | 4 (5.7) | 0.83 |
| Baseline nbDMARD use (%) | 91 (81.2) | 20 (71.4) | 71 (84.5) | 0.29 |
*Data for categorical variables is presented as percentage of non-missing data. nbDMARDs listed are the most frequently used in the cohort.
BMI, body mass index; DAS28, Disease Activity Score in 28 joints; ESR, erythrocyte sedimentation rate; nbDMARD, non-biologic disease-modifying antirheumatic drug; RF, rheumatoid factor.
Bold typeface indicates significance at p<0.05.