Table 2.
Comparison of baseline characteristics between patients with RA-ILD according to radiological pattern (UIP and NSIP).
| Variable | UIP, n = 71 | NSIP, n = 41 | p Value |
|---|---|---|---|
| Epidemiological characteristics | |||
| Female sex, n (%) | 31 (43.7) | 30 (73.2) | 0.003 |
| Caucasian, n (%) | 68 (95.8) | 41 (100) | 0.182 |
| Age, years, mean (SD) | 68.9 (9.4) | 68.0 (10.9) | 0.639 |
| Clinical and analytical characteristics | |||
| Current smoker | 0.815 | ||
| Nonsmoker, n (%) | 32 (45.1) | 21 (51.2) | |
| Smoker, n (%) | 13 (18.3) | 7 (17.1) | |
| Exsmoker, n (%) | 26 (36.6) | 13 (31.7) | |
| Body mass index, mean (SD) | 28.1 (4.3) | 27.5 (4.1) | 0.578 |
| Time since diagnosis of RA, months, median (25%–75%) | 146.1 (69.2–227.9) | 167.7 (87.5–224.2) | 0.987 |
| Diagnostic delay, months, median (25%–75%) | 10.9 (4.9–18.4) | 7.0 (4.9–15.5) | 0.395 |
| Time since diagnosis of ILD, months, mean (SD) | 23.8 (9.6–59.9) | 36.4 (11.3–67.9) | 0.337 |
| Positive rheumatoid factor (>10), n (%) | 69 (97.2) | 38 (92.7) | 0.267 |
| ACPA titer (>20), n (%) | 65 (91.5) | 31 (75.6) | 0.020 |
| Erosive disease, n (%) | 53 (74.6) | 22 (53.7) | 0.023 |
| Sjögren syndrome, n (%) | 11 (15.5) | 7 (17.1) | 0.826 |
| Osteoporosis, n (%) | 32 (45.1) | 17 (41.5) | 0.711 |
| Treatment | |||
| Synthetic DMARD | 60 (84.5) | 37 (90.2) | 0.390 |
| Methotrexate, n (%) | 28 (39.4) | 22 (50.7) | 0.145 |
| Leflunomide, n (%) | 20 (28.2) | 9 (22.0) | 0.469 |
| Sulfasalazine, n (%) | 7 (9.9) | 1 (2.4) | 0.142 |
| Hydroxychloroquine, n (%) | 14 (19.7) | 7 (17.1) | 0.730 |
| Biologic DMARD | 30 (42.3) | 19 (46.3) | 0.674 |
| Infliximab, n (%) | 1 (1.4) | 0 (0.0) | 0.445 |
| Etanercept, n (%) | 3 (4.2) | 3 (4.2) | 0.485 |
| Adalimumab, n (%) | 1 (1.4) | 2 (4.9) | 0.273 |
| Golimumab, n (%) | 2 (2.8) | 1 (2.4) | 0.905 |
| Certolizumab, n (%) | 2 (2.8) | 1 (2.4) | 0.905 |
| Tocilizumab, n (%) | 4 (4.2) | 1 (2.4) | 0.324 |
| Abatacept, n (%) | 9 (12.7) | 6 (14.6) | 0.769 |
| Rituximab, n (%) | 9 (12.7) | 4 (9.8) | 0.642 |
| Immunosuppressants | 7 (9.9) | 4 (9.8) | 0.986 |
| Mycophenolate, n (%) | 5 (7.0) | 2 (4.9) | 0.649 |
| Azathioprine, n (%) | 2 (2.8) | 2 (4.9) | 0.571 |
| Antifibrotic agents, nintedanib, n (%) | 1 (0.9) | 0 (0.0) | 0.045 |
| Corticosteroids at baseline, n (%) | 42 (59.1) | 22 (50.7) | 0.800 |
| Dose of corticosteroids at baseline, median (25%–75%) | 5.0 (0.0–6.0) | 5.0 (0.0–7.5) | 0.140 |
RA: rheumatoid arthritis; ILD: interstitial lung disease; DMARD: disease-modifying antirheumatic drug; SD: standard deviation; ACPA, anticyclic citrullinated protein antibody.