Table 1.
Clinical characteristics of the patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD), which have been classified according to the presence or absence of usual interstitial pneumonia (UIP) pattern in high resolution computed tomography (HRCT)
| Characteristics | RA-ILD | RA-UIP | RA-non-UIP | P-value |
|---|---|---|---|---|
| (n = 59) | (n = 35, 59.3 %) | (n = 24, 40.7 %) | (UIP vs. non-UIP) | |
| Gender | ||||
| ᅟMale | 33 (55.9) | 19 (54.3) | 14 (58.3) | 0.758 |
| ᅟFemale | 26 (44.1) | 16 (45.7) | 10 (41.7) | |
| Smokinga | ||||
| ᅟNever | 23 (39.7) | 14 (41.2) | 9 (37.5) | 0.778 |
| ᅟEx-smoker | 26 (44.8) | 14 (41.2) | 12 (50.0) | |
| ᅟCurrent smoker | 9 (15.5) | 6 (17.6) | 3 (12.5) | |
| Age (y) | 66 ± 11.1 | 66 ± 11.9 | 67 ± 10.0 | 0.597 |
| Serology | ||||
| ᅟPositive RFb | 48 (84.2) | 29 (85.3) | 19 (82.6) | 1.000 |
| ᅟPos. ANAc | 8 (17.8) | 5 (20.0) | 3 (15.0) | 0.716 |
| ᅟPos. anti-CCP antibodyd | 17 (60.8) | 10 (71.4) | 7 (63.6) | 0.504 |
| Dyspneab | 35 (61.4) | 25 (73.5) | 10 (43.5) | 0.022 |
| Coughe | 31 (60.8) | 17 (60.7) | 14 (60.9) | 0.991 |
| Inspiratory crackles | 41 (69.5) | 29 (82.9) | 12 (50.0) | 0.007 |
| FVC % pred | 85 ± 17.0 | 82 ± 17.1 | 89 ± 16.5 | 0.164 |
| DLCO % pred | 71 ± 18.1 | 72 ± 20.7 | 70 ± 13.3 | 0.635 |
| Medications | ||||
| ᅟSteroids, ever | 54 (91.5) | 32 (91.4) | 22 (91.7) | 1.000 |
| ᅟMTX, ever | 35 (59.3) | 18 (51.4) | 17 (70.8) | 0.136 |
| ᅟMTX, when ILD diagnosed | 15 (25.4) | 6 (17.1) | 9 (37.5) | 0.078 |
| ᅟBiological drugs, ever | 14 (23.7) | 7 (20.0) | 7 (29.2) | 0.416 |
Data presented as n (percentage) or mean ± SD. P-values calculated using Fisher test, χ 2- test or independent T-test
RA-UIP usual interstitial pneumonia (UIP) pattern in patients with rheumatoid arthritis (RA). RA-non-UIP Rheumatoid arthritis patients with other than UIP-pattern interstitial lung disease (ILD). FVC forced vital capacity. DLCO diffusing capacity of the lung for carbon monoxide. % pred: percentage of the predicted value. RF: rheumatoid factor. ANA: anti-nuclear antibodies. MTX: methotrexate. CCP: cyclic citrullinated peptide
adata missing from 1 RA-UIP patient
bdata missing from 2 patients (1 RA-UIP, 1 RA-non-UIP)
cdata missing from 14 patients (10 RA-UIP, 4 RA-non-UIP)
edata missing from 34 patients (21 RA-UIP, 13 RA-non-UIP)
fdata missing from 8 patients (7 RA-UIP, 1 RA-non-UIP)