Table 2 Clinical characteristics of patients between the CTD-ILD and CTD-NILD groups

RA

8 (24.2%)

9 (29.0%)

0.054

0.665

pSS

6 (18.2%)

7 (22.6%)

0.055

0.662

SSc

5 (15.2%)

3 (9.7%)

0.082

0.508

DM/PM

4 (12.1%)

3 (9.7%)

0.039

0.754

AAV

4 (12.1%)

3 (9.7%)

0.039

0.754

UCTD

6 (18.2%)

6 (19.4%)

0.015

0.904

Positive anti-CCP antibody

4 (12.1%)

4 (12.9%)

0.000

1.000

Positive ANA antibody

24 (72.7%)

18 (58.1%)

1.523

0.217

Positive SSA antibody

8 (24.2%)

12 (38.7%)

1.557

0.212

Positive SSB antibody

4 (12.1%)

8 (25.9%)

1.169

0.280

Positive p-ANAC antibody

8 (24.2%)

11 (35.5%)

0.968

0.325

Positive c-ANAC antibody

1 (3.0%)

1 (3.2%)

0.000

1.000

ESR (mm/h)

22.00 (9.50–38.50)

29.00 (12.00–51.00)

− 0.974

0.330

CRP (mg/L)

3.90 (1.90–9.65)

5.70 (1.80–21.20)

− 0.363

0.717

RF (IU/mL)

20.10 (20.00–167.00)

21.80 (20.00–42.30)

− 0.233

0.816

IgM (g/L)

1.20 (0.95–1.73)

1.17 (0.87–1.97)

− 0.013

0.989

IgA (g/L)

3.30 ± 1.89

2.89 ± 1.12

− 0.598

0.550

IgG (g/L)

13.40 (11.60–16.60)

13.50 (12.00–15.80)

− 0.114

0.909

C3 (g/L)

0.91 ± 0.30

0.91 ± 0.28

− 0.430

0.667

C4 (g/L)

0.22 (0.18–0.29)

0.22 (0.14–0.28)

− 0.282

0.778

Mean FEV₁ (n = 25)

91.30 ± 15.16

–

–

–

Mean FVC (n = 25)

84.26 ± 14.26

–

–

–

Mean DL_CO% (n = 25)

61.74 ± 13.90

–

–

–

Mean HRCT scores

8.24 ± 4.21

–

–

–