Table 2 Factors related to the presence of RA-ILD in RA patients

Age, years

1.082 (1.059, 1.106)

<0.001

1.017 (0.979, 1.056)

0.393

Sex (ref. female)

3.254 (2.110, 5.020)

<0.001

0.969 (0.392, 2.393)

0.945

BMI ≥ 23 kg/m² (ref. BMI < 23 kg/m²)

1.372 (0.938, 2.006)

0.103

1.650 (1.036, 2.629)

0.035

Ever-smoker (ref. never-smoker)

2.844 (1.876, 4.311)

<0.001

2.484 (1.071, 5.764)

0.034

Age at RA diagnosis

1.081 (1.060, 1.102)

<0.001

1.056 (1.021, 1.091)

0.001

Late-onset RA (ref. younger-onset RA)

4.753 (3.100, 7.286)

<0.001

Disease duration of RA

0.949 (0.921, 0.977)

0.001

RF positivity (ref. RF negative)

2.000 (1.127, 3.549)

0.018

1.222 (0.630, 2.369)

0.552

Anti-CCP positivity (ref. Anti-CCP negative) (n = 554)

1.070 (0.540, 2.117)

0.847

Either RF or anti-CCP positivity (n = 554)

0.659 (0.258, 1.686)

0.385

ESR

1.021 (1.013, 1.030)

<0.001

CRP

1.489 (1.239, 1.790)

<0.001

DAS28-ESR

1.244 (1.074, 1.440)

0.004

0.952 (0.739, 1.228)

0.706

DAS28-CRP

1.161 (0.970, 1.391)

0.104

CDAI

1.017 (0.993, 1.041)

0.166

SDAI

1.022 (1.000, 1.044)

0.052

HAQ ≥ 1 (ref. HAQ <1)

1.794 (1.220, 2.638)

0.003

1.294 (0.768, 2.179)

0.333

Methotrexate use (ref. not used)

0.246 (0.163, 0.372)

<0.001

0.251 (0.154, 0.410)

<0.001

Biologic DMARDs use (ref. not used)

0.688 (0.425, 1.112)

0.127

Oral Glucocorticoid use (ref. not used)

3.954 (2.661, 5.877)

<0.001

3.853 (2.320, 6.400)

<0.001