Table 1.
Baseline characteristics of the patients in the Chinese RA cohort, by degree of ILD*
| RA–no ILD (ILA score 0) (n = 50) |
RA–indeterminate ILD (ILA score 1) (n = 42) |
RA–mild ILD (ILA score 2) (n = 38) |
RA–advanced ILD (ILA score 3) (n = 3) |
RA-ILD (ILA score 2 or 3) (n = 41) |
|
|---|---|---|---|---|---|
| Demographic parameters | |||||
| Age, years | 43.4 ± 15.54 | 57.07 ± 9.40† | 51.74 ± 13.80† | 69.33 ± 8.96† | 53.02 ± 14.20† |
| Female, no. (%) | 41 (82) | 34 (81) | 29 (76) | 0 (0)† | 29 (71) |
| Ever smoker, no. (%) | 6 (12) | 3 (7) | 2 (5) | 3 (100)† | 5 (12) |
| Pack-years of smoking | 15.50 ± 14.26 | 7.50 ± 6.61 | 21.25 ± 12.37 | 11.33 ± 8.08 | 15.30 ± 10.02 |
| RA parameters | |||||
| RF, IU/ml | 180.63 ± 228.61 | 319.53 ± 474.89 | 744.48 ± 1,987.64† | 1,435.33 ± 1,891.62† | 795.03 ± 1,966.34† |
| Anti-CCP, units/ml | 179.25 ± 169.33 | 232.29 ± 185.99 | 252.64 ± 187.54 | 287.90 ± 216.79 | 255.22 ± 187.01† |
| DAS28 | 4.06 ± 1.49 | 4.45 ± 1.30 | 4.92 ± 1.25† | 4.40 ± 1.53 | 4.88 ± 1.26† |
| Duration of RA, years | 4.31 ± 4.34 | 6.26 ± 8.68 | 5.90 ± 5.29 | 1.67 ± 0.58 | 5.59 ± 5.21 |
| Medication use (current), no. (%) | |||||
| Prednisone | 3 (16) | 12 (29)† | 11 (29)† | 2 (67)† | 13 (32)† |
| Methotrexate | 49 (100) | 40 (98) | 37 (97) | 2 (67) | 39 (95) |
| Leflunomide | 21 (42) | 16 (39) | 15 (39) | 0 (0) | 15 (37) |
| TNFα inhibitor | 3 (6) | 1 (2) | 3 (8) | 0 (0) | 3 (7) |
| Respiratory parameters, no. (%) | |||||
| Cough | 0 (0) | 0 (0) | 3 (8) | 2 (67)† | 5 (12)† |
| Dyspnea | 1 (2) | 1 (2) | 5 (13) | 3 (100)† | 8 (20)† |
| Spirometric parameters | |||||
| FEV1, percent of predicted | 83.56 ± 14.25 | 76.91 ± 13.81† | 79.73 ± 15.17 | 75.00 ± 26.66 | 79.33 ± 15.90 |
| FVC, percent of predicted | 83.77 ± 12.84 | 75.55 ± 10.36† | 77.15 ± 13.42 | 72.33 ± 14.19 | 76.76 ± 13.35† |
| DLCO, percent of predicted | 90.4 ± 19.34 | 74.06 ± 18.89† | 74.53 ± 22.53† | 59.33 ± 5.03† | 73.30 ± 22.01† |
*
Data in some categories were missing for some patients, as follows: prednisone, leflunomide, or tumor necrosis factor α (TNFα) use (1 patient), methotrexate use (2 patients), forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) (20 patients), and diffusing capacity for carbon monoxide (DLCO) (26 patients).
Except where indicated otherwise, values are the mean ± SD.
ILA = interstitial lung abnormality; RF = rheumatoid factor; anti-CCP = anti–cyclic citrullinated peptide; DAS28 = 28-joint Disease Activity Score.
†
P < 0.05 versus the group of rheumatoid arthritis (RA) patients without interstitial lung disease (ILD).