Summary of baseline covariates (age and duration/times in yrs). DMARD use at time of baseline US examination in clinical remission using the combined score to define residual US synovitis. N = no. available observations. Values are median (IQR) unless otherwise specified.
| Baseline Covariates | All, n = 321 | US−, n = 134 | US+, n = 187 | p |
|---|---|---|---|---|
| Age, yrs | 54 (45–63) | 53.5 (44–63.8) | 55 (45–62) | 0.70 |
| Female, % | 74 | 74 | 74 | 1 |
| Disease duration, yrs | 4.7 (2.1–9.8) | 4.8 (2.4–9.1) | 4.7 (2–10.2) | 0.75 |
| Seropositive, n (%) | 313 (84) | 129 (82) | 184 (85) | 0.54 |
| DAS28 | 1.9 (1.5–2.2) | 1.9 (1.5–2.2) | 1.9 (1.6–2.2) | 0.48 |
| DMARD treatment, % | ||||
| bDMARD | 64 | 60 | 66 | 0.13 |
| sDMARD | 31 | 31 | 30 | |
| No DMARD | 6 | 9 | 4 | |
| Time in remission before, left imputation, mode 2, yrs | 1 (0.5–2) | 1.3 (0.6–2.2) | 0.8 (0.4–1.6) | < 0.001 |
| Time in remission before, right imputation, mode 1, yrs | 0 (0–0.4) | 0 (0–0.6) | 0 (0–0.3) | 0.56 |
DAS28: 28-joint Disease Activity Score; bDMARD: biologic disease-modifying antirheumatic drugs; sDMARD: synthetic DMARD; US±: with or without US-detected residual synovitis; IQR: interquartile range; US: ultrasound.