Table 1.
Characteristics of the RA patients.
| ILD(+)RA | ILD(−)RA | P | ||
|---|---|---|---|---|
| Number | 17 | 17 | ||
| Age | Years | 67.0 (9.5) | 65.8 (7.2) | *0.8092 |
| Males | n (%) | 8 (47.1) | 2 (11.8) | 0.0570 |
| Disease duration | Years | 12.4 (7.7) | 18.7 (11.3) | *0.0755 |
| Steinbrocker stage III and IV | n (%) | 9 (52.9) | 13 (76.5) | 0.2818 |
| Smoker or past smoker | n (%) | 7 (41.2) | 3 (17.6) | 0.2451 |
| Rheumatoid factor-positive | n (%) | 15 (88.2) | 15 (88.2) | 1.0000 |
| Anti-citrullinated peptide Ab-positive | n (%) | 14 (82.4) | 13 (76.5) | 1.0000 |
| KL-6 | U/mL | 605.4 (418.4) | 258.9 (131.1) | *0.0005 |
| SP-D | ng/mL | 91.4 (84.4) | 45.7 (36.5) | *0.1165 |
Notes: Average values of each group are shown. Standard deviations or percentages are shown in parenthesis. Differences were tested by Mann-Whitney’s U test or Fisher’s exact test using 2 × 2 contingency tables.
*
Mann–Whitney’s U-test was employed.
Abbreviations: RA, rheumatoid arthritis; ILD(+)RA, RA with ILD; ILD(−)RA, RA without ILD; Ab, antibody; KL-6, Krebs von den lungen-6; SP-D, surfactant protein-D.