Table 1 Baseline clinical characteristics of patients with CTD-ILD, CTD-non-ILD and HCs

Age, years

57.5 (46–63)

42.5 (28.8–63.0)

61.0 (53–68.5)

< 0.001***

Male, n (%)

8 (26.7)

6 (20)

17 (28)

0.417

Smoking history, n (%)

3 (10)

2 (15)

10 (16)

0.324

Prior immunosuppressant use, n (%)

N/A

21 (70)

39 (63.9)

0.566

LDH, U/L

N/A

245.0 (183.8–310.0)

285.0 (216.5–339.0)

0.111

CRP, mg/L

N/A

7.2 (2.6–21.3)

6.5 (3.6–22.0)

0.976

ESR, mm/h

N/A

37.0 (15.8–67.0)

37.0 (15.0–56.0)

0.780

WBC count, × 10⁹/L

N/A

5.9 (3.8–8.8)

6.7 (4.8–9.8)

0.253

Lymphocytes count, × 10⁹/L

N/A

1.1 (0.8–1.7)

1.2 (0.7–1.7)

0.879

NLR

N/A

3.8 (1.9–5.7)

4.4 (2.4–7.3)

0.265

RDW %

N/A

13.7 (12.60–14.5)

13.5 (12.7–14.4)

0.966

TBil, umol/L

N/A

5.7 (4.3–8.3)

7.1 (6.0–10.2)

0.046*

CD3 + CD4 + T cells, n/mm³

N/A

430.0 (218.0–535.0)

438.0 (245.0–725.0)

0.445

CD3 + CD8 + T cells, n/mm³

N/A

451 (285–1012)

432.0 (207.0–762.0)

0.244

sPAH, mmHg

N/A

27 (25–30)

32 (25–36)

0.001**

Subtype of CTD

pSS, n (%)

N/A

6 (20.0)

20 (32.8)

0.204

PM/DM, n (%)

N/A

7 (23.3)

14 (23.0)

0.968

UCTD, n (%)

N/A

13 (43.3)

15 (24.6)

0.069

RA, n (%)

N/A

4 (13.3)

12 (19.7)

0.455

FVC %predicted

N/A

N/A

65.6 (42.9–83.6) (n = 30)

DLCO %predicted

N/A

N/A

51.8 (42.1–73.2) (n = 30)

N/A

PaO2/FiO2 ratio

N/A

N/A

350 (286–414.3)

N/A

Total GGO score

N/A

N/A

19.0 (14.0–22.2)

N/A

Total fibrosis score

N/A

N/A

6.0 (5.0–10.7)

N/A