Table 1.
Comparison in selected clinical variables between patients with RA and interstitial lung disease (RA-ILD) and patients with RA without interstitial lung disease (RA only).
| Variable | RA patients groups | P | |
|---|---|---|---|
| RA-ILD n = 39 | RA only n = 42 | ||
| Age, years | 51.0 (36.0–72.0) | 49.0 (24.0–73.0) | 0.21 |
| Smoking history, n (%) | 9 (23.1) | 13 (31.0) | 0.46 |
| Current smokers, n (%) | 1 (2.6) | 6 (14.3) | 0.11 |
| RA characteristics | |||
| Disease duration, years | 7.0 (1.0–35.0) | 6.5 (0.75–25.0) | 0.26 |
| DAS28 (units) | 3.9 (1.7–5.3) | 2.5 (1.7–5.1) | <0.001 |
| Inactive (<2.8) | 13 (33.3) | 29 (69.0) | 0.002 |
| Active (≥2.8) | 26 (66.7) | 13 (31.0) | |
| HAQ-Di (units) | 0.8 (0.2–3.0) | 0.4 (0.2–2.4) | <0.001 |
| Impairment in HAQ-Di ≥0.6, n (%) | 29 (74.4) | 14 (33.3) | <0.001 |
| Global functional status III-IV, n (%) | 21 (44.7) | 0 (0%) | — |
| Steinbrocker stage-hands, III or IV, n (%) | 6 (12.8) | 0 (0%) | — |
| Rheumatoid nodules history, n (%) | 29 (74.4) | 5 (14.7) | <0.001 |
| ESR, mm/h | 32.0 (14.0–62.0) | 19.5 (8.0–45.0) | <0.001 |
| Positive RF, n (%) | 38 (97.4) | 15 (35.7) | <0.001 |
| Anti-CCP titers | 77.9 (25.2–200.0) | 30.2 (7.0–70.14) | <0.001 |
| Positive anti-CCP | 39 (100) | 27 (64.3) | <0.001 |
| DMARDs | |||
| Methotrexate, n (%) | 39 (100) | 41 (97.6) | 1.00 |
| At the time of the study, mg/week | 15.0 (10.0–22.5) | 7.5 (0–12.5) | <0.001 |
| MTX treatment duration, years | 7.0 (2.5–30.0) | 5.0 (0.8–13.0) | 0.002 |
| MTX accumulated doses, grams | 6.8 (3.1–129.6) | 1.1 (0–2.1) | <0.001 |
| Azathioprine, n (%) | 27 (69.2) | 21 (50.0) | 0.11 |
| Chloroquine, n (%) | 10 (25.6) | 19 (45.2) | 0.10 |
| Corticosteroids utilization, n (%) | 37 (94.9) | 37 (88.1) | 0.43 |
Qualitative variables were expressed in frequency (%); quantitative variables were expressed in medians (ranges); RA: rheumatoid arthritis; ILD: interstitial lung disease; ESR: erythrocyte sedimentation rate; VAS: visual analogue scale; HAQ-Di: Health Assessment Questionnaire-Disability Index; RF: rheumatoid factor; anti-CCP2: anti-cyclic citrullinated peptide antibodies (second generation); DMARDs: disease-modifying antirheumatic drugs. P values for comparisons between medians were computed with Mann-Whitney U test and for comparison between proportions were computed with chi-square (or Fisher exact test if applicable).