Table 1.
Characteristics of RA patients.
|
ILD(+) RA case 1 + 2 |
CLD(–)RA control 1 + 2 | P |
UIP(+)RA case 1 |
CLD(–)RA control 1 | P |
NSIP(+)RA case 2 |
CLD(–)RA control 2 | P | |
|---|---|---|---|---|---|---|---|---|---|
| Number | 100 | 100 | 46 | 46 | 54 | 54 | |||
| Mean age, years (SD) | 67.3 (8.5) | 66.2 (8.9) | 0.3678 | 67.2 (9.1) | 66.6 (9.0) | 0.7473 | 67.3 (8.1) | 65.8 (8.8) | 0.3481 |
| Male, n (%) | 24 (24.0) | 24 (24.0) | 1.0000* | 16 (34.8) | 16 (34.8) | 1.0000* | 8 (14.8) | 8 (14.8) | 1.0000* |
| Age at onset, years (SD) | 54.0 (13.6) | 51.7 (12.7) | 0.2205 | 54.0 (14.3) | 51.7 (13.6) | 0.4349 | 54.1 (13.0) | 51.8 (12.1) | 0.3456 |
| Steinbrocker stage III and IV, n (%) | 49 (49.0) | 54 (54.5) | 0.4792* | 25 (54.3) | 24 (52.2) | 1.0000* | 24 (44.4) | 30 (56.6) | 0.2480* |
| Smoker or past smoker, n (%) | 37 (38.1) | 29 (32.6) | 0.4471* | 18 (40.9) | 18 (45.0) | 0.8258* | 19 (35.8) | 11 (22.4) | 0.1919* |
| RF, IU/ml (SD) | 564.6 (1,302.2) | 154.3 (241.2) | 0.0022 | 523.0 (1,009.2) | 138.0 (205.6) | 0.0131 | 598.5 (1,508.2) | 168.1 (269.0) | 0.0414 |
| ACPA, IU/ml (SD) | 374.6 (830.3) | 252.5 (293.4) | 0.1680 | 289.0 (302.6) | 269.5 (290.5) | 0.7574 | 442.7 (1,079.5) | 238.0 (297.8) | 0.1821 |
| KL-6, U/ml (SD) | 762.9 (647.5) | 322.7 (400.4) | 1.41 × 10−5 | 749.9 (652.6) | 277.5 (128.1) | 0.0014 | 772.9 (649.5) | 354.9 (513.7) | 0.0029 |
| SP-D, ng/ml (SD) | 128.8 (148.3) | 46.1 (31.3) | 0.0002 | 128.6 (92.6) | 48.6 (23.1) | 0.0004 | 129.0 (182.7) | 44.2 (36.3) | 0.0179 |
| Corticosteroid administration, n (%) | 75 (75.0) | 75 (75.0) | 1.0000* | 36 (78.3) | 36 (78.3) | 1.0000* | 39 (72.2) | 39 (72.2) | 1.0000* |
| csDMARDs administration, n (%) | 86 (86.0) | 86 (86.0) | 1.0000* | 42 (91.3) | 42 (91.3) | 1.0000* | 44 (81.5) | 44 (81.5) | 1.0000* |
| b/tsDMARDs administration, n (%) | 27 (27.0) | 27 (27.0) | 1.0000* | 13 (28.3) | 13 (28.3) | 1.0000* | 14 (25.9) | 14 (25.9) | 1.0000* |
RA, rheumatoid arthritis; ILD, interstitial lung disease; UIP, usual interstitial pneumonia; NSIP, non-specific interstitial pneumonia; CLD, chronic lung disease; SD, standard deviation; RF, Rheumatoid factor; ACPA, Anti-citrullinated peptide antibody; KL-6, Krebs von den lungen-6; SP-D, Surfactant protein-D; csDMARDs, conventional synthetic disease-modifying antirheumatic drugs; b/tsDMARDs, biological/targeted synthetic disease-modifying antirheumatic drugs; ILD(+)RA, RA patients with ILD; CLD(–)RA, RA patients without CLD; UIP(+)RA, RA patients with UIP; NSIP(+)RA, RA patients with NSIP. Numbers or average values of each group are shown. Standard deviations or percentages are shown in parenthesis. Difference was tested in the comparison with the CLD(–) population by Fisher's exact test using 2 × 2 contingency tables or Student's t-test.
Fisher's exact test was employed.