Table 1.
Demographic and phenotypic spectrum of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and RA without ILD.
| Characteristics | All (N=96) | Patients with RA (N=51) | Patients with RA-ILD (N=45) | p-Value |
|---|---|---|---|---|
| Male gender. No./Total No. (%) | 32/96 (33.3) | 14/51 (27.4) | 18/45 (40.0) | 0.203 |
| Age at inclusion (years) | 55.5±11.6 | 46.1±12.2 | 59.5±8.7 | <0.001* |
| Age at onset of RA (years) | 47.5±13.2 | 40.4±11.7 | 54.0±12.2 | 0.005* |
| Duration of RA (years) | 6.8±5.6 | 6.0±4.2 | 7.2±6.2 | 0.549 |
| Age at onset of ILD (years) | 56.1±7.8 | |||
| Duration of ILD (years) | 2.2±1.7 | |||
| Ever smoker. No./Total No. (%) | 16/96 (16.7) | 7/51 (13.7) | 9/45 (20.0) | 0.427 |
| Manifestation of RA | ||||
| Erosive disease. No./Total No. (%) | 75/96 (78.1) | 44/51 (86.4) | 31/45 (68.9) | 0.051 |
| Laboratory indicators | ||||
| ACPA titer | 900.9±1042.8 | 423.4±697.0 | 1139.6±1112.8 | 0.012* |
| Rheumatoid factor titer | 294.8±659.0 | 112.4±121.6 | 372.2±773.0 | 0.220 |
| ESR | 31.5±24.4 | 22.2±15.5 | 36.0±26.7 | 0.033* |
| Pattern of HRCT | ||||
| NSIP or possible NSIP. No./Total No. (%) | 6/45 (13.3) | |||
| UIP or possible UIP. No./Total No. (%) | 18/45 (40.0) | |||
| Pulmonary function | ||||
| Forced vital capacity (% of predicted value) | 79.9±20.1 | |||
| DLCO (% of predicted value) | 58.4±13.4 | |||
| Total lung capacity (% of predicted value) | 79.4±18.6 | |||
| Treatments | ||||
| Pred | 45/96 (46.9) | 14/51 (27.4) | 31/45 (68.9) | 0.001* |
| MTX | 31/96 (32.3) | 628/51 (54.9) | 3/45 (6.7) | <0.001* |
| CTX | 11/96 (11.5) | 0/51 (0) | 11/45 (24.4) | 0.008* |
RA – rheumatoid arthritis; ILD – interstitial lung disease; ACPA – anti-citrullinated protein antibody; ESR – erythrocyte sedimentation rate; NSIP – non-specific interstitial pneumonia; UIP – usual interstitial pneumonia; DLCO – diffusion capacity for carbon monoxide; PRED – prednisone; MTX – methotrexate; CTX – cyclophosphamide; HRCT – high-resolution computed tomography.