Table 4.
Risk factors for interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA)*
| Risk Factor | RA patients with ILD (N=46) | RA patients without ILD (N=536) | Hazard Ratio† | 95% CI† |
|---|---|---|---|---|
| Male gender, N (%) | 27 (58.7%) | 128 (23.9) | 4.37 | 2.43, 7.88 |
| Age at RA onset in years (mean ± SD) | 56.8 ± 14.7 | 57.8 ± 15.2 | 1.41 | 1.11, 1.79 |
| Smoking (ever), N (%) | 30 (65.2) | 278 (51.9) | 1.60 | 0.87, 2.94 |
| Extraarticular disease (ever), N (%) | 6 (13.0) | 80 (14.9) | 1.48 | 0.58, 3.79 |
| Rheumatoid factor (ever), N (%) | 33 (73.3) | 341 (67.0) | 1.84 | 0.91, 3.71 |
| Erosions (ever), N (%) | 10 (25.0) | 83 (17.4) | 1.92 | 0.92, 4.02 |
| Destructive joint changes (ever), N (%) | 27 (67.5) | 271 (56.7) | 2.37 | 1.18, 4.76 |
| ESR - 3 values ≥ 60 (ever), N (%) | 21 (45.7) | 149 (27.8) | 3.52 | 1.94, 6.38 |
| Large joint swelling (ever), N (%) | 39 (84.8) | 448 (83.6) | 1.90 | 0.83, 4.36 |
| Rheumatoid nodules (ever), N (%) | 21 (45.7) | 168 (88.9) | 2.60 | 1.41, 4.79 |
| DMARD use (ever), N (%) | 27 (58.7) | 306 (57.1) | 1.82 | 0.97, 3.41 |
| Methotrexate use (ever), N (%) | 12 (26.1) | 116 (31.3) | 2.31 | 1.15, 4.63 |
| Steroid use (ever), N (%) | 24 (52.2) | 287 (53.5) | 2.01 | 1.12, 3.63 |
| Functional capacity†† = 1+2, N (%) | 33 (71.7) | 425 (79.9) | 2.17 (3,4 versus 1,2) | 1.14, 4.16 |
| Functional capacity†† = 3+4, N (%) | 13 (28.3) | 107 (20.1) |
*
Except where indicated otherwise, values are the number (%) of patients.
†
Models in rows 4–14 are adjusted for age at RA, sex, and ever smoker.
††
According to Steinbrocker index;
ILD = interstitial lung disease; RA = rheumatoid arthritis; CI = confidence interval; ESR = erythrocyte sedimentation rate; DMARD = disease modifying antirheumatic drug