TABLE 1.
Demographic and clinical characteristics of all the patients included in the study.
| RA-ILD+ n = 21 | RA-ILD− n = 25 | IPF n = 21 | p RA-ILD+ vs. RA-ILD−/RA-ILD+ vs. IPF | |
|---|---|---|---|---|
| Sex (women), n (%) | 9 (45.9) | 15 (60.0) | 7 (33.3) | 0.84/0.53 |
| Age at study (years), mean ± SD | 66.5 ± 10.1 | 60.1 ± 11.8 | 69.2 ± 10.0 | 0.05/0.38 |
| Smoking ever, n (%) | 13 (65.0) | 13 (52.0) | 16 (76.2) | 0.50/0.32 |
| RA duration (years), mean ± SD | 9.2 ± 10.2 | 4.1 ± 7.4 | — | 0.06/— |
| CRP (mg/dl), mean ± SD | 1.1 ± 1.1 | 0.5 ± 0.5 | — | 0.04/— |
| ESR (mm/1st hour), mean ± SD | 22.8 ± 27.2 | 14.4 ± 12.4 | — | 0.24/— |
| Disease activity | — | |||
| DAS28-CRP, mean ± SD | 3.4 ± 1.4 | 2.2 ± 1.1 | — | <0.01/— |
| DAS28-ESR, mean ± SD | 3.4 ± 1.8 | 2.6 ± 1.6 | — | 0.12/— |
| Antibody status | — | |||
| RF+, n (%) | 17 (81.0) | 11 (44.0) | — | 0.01/— |
| ACPA+, n (%) | 19 (90.4) | 15 (60.0) | — | 0.02/— |
| Pulmonary function tests | ||||
| FVC (% predicted), mean ± SD | 95.2 ± 24.1 | 99.2 ± 16.0 | 84.9 ± 14.7 | 0.58/0.10 |
| FEV1 (% predicted), mean ± SD | 92.2 ± 21.0 | 94.9 ± 22.0 | 87.3 ± 19.6 | 0.67/0.43 |
| FEV1/FVC (% predicted), mean ± SD | 77.8 ± 9.1 | 93.6 ± 12.3 | 79.7 ± 7.8 | <0.01/0.47 |
| DLCO (% predicted), mean ± SD | 43.3 ± 15.9 | 79.9 ± 20.0 | 43.6 ± 18.4 | <0.01/0.97 |
| HRCT | ||||
| Pulmonary involvement | 21 (100.0) | 0 (0.0) | 21 (100.0) | — |
| UIP pattern, n (%) | 11 (52.4) | — | 21 (100.0) | — |
| Probable UIP pattern, n (%) | 2 (9.5) | — | 0 (0.0) | — |
| NSIP pattern, n (%) | 7 (33.3) | — | 0 (0.0) | — |
| Non-NSIP pattern, n (%) | 1 (4.8) | — | 0 (0.0) | — |
RA, rheumatoid arthritis; ILD, interstitial lung disease; IPF, idiopathic pulmonary fibrosis; SD, standard deviation; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; DAS, disease activity score; RF, rheumatoid factor; ACPA, anti-cyclic citrullinated peptide antibodies; FVC, forced vital capacity; FEV1, forced expiratory volume at first second; DLCO, diffusing capacity of the lung for carbon monoxide; HRCT, high resolution computed tomography; UIP, usual interstitial pneumonia; NSIP, non-specific interstitial pneumonia. Significant results are highlighted in bold.