Table 1 Characteristics of patients with interstitial lung disease associated with connective tissue disease (CTD-ILD), undifferentiated CTD-ILD (UCTD-ILD), chronic fibrosing interstitial lung disease (CFIP), and control subjects

Subjects, n

26

19

16

33

Age, years

64 (59–81)

67 (54–80)

70 (53–79)

63 (39–83)

0.0265

Females, n (%)

16 (61)

3 (15)

8 (50)

22 (66)

0.0032

Smoking status

 Former smoker, n (%)

7 (26)

12 (63)

8 (50)

11 (33)

0.0617

 Current smoker, n (%)

1 (3)

2 (10)

1 (6)

0 (0)

0.3250

 Pack-years

0 (0–40)

30 (0–150)

5 (0–70)

0 (0–100)

0.0035

P_{a, O2} mmHg

83.6 (62.4–111.7)

72.5 (58.8–86.6)

79.2 (42.3–105.2)

0.1413

KL-6, U · mL⁻¹

261 (140–491)

1581 (304–8298)

1045 (363–4560)

1117 (289–3943)

<0.0001

SP-D, ng · mL⁻¹

32.3 (8.6–126.0)

292.5 (32.3–1070)

206.0 (88.6–405)

175.0 (31.2–994.0)

<0.0001

BAFF, ng · mL⁻¹

0.6 (0.5–0.9)

1.0 (0.3–1.9)

1.8 (1.0–2.3)

2.0 (0.6–16.7)

<0.0001

VC, L

1.9 (0.9–3.1)

2.1 (0.9–3.1)

2.0 (1.0–3.5)

0.9213

VC, % pred

59.8 (35.4–128.2)

69.2 (37.9–97.4)

65.4 (41.3–104.1)

0.3390

DL,_CO, mL · min⁻¹ · mmHg⁻¹

9.3 (3.4–15.4)

8.9 (4.5–16.9)

10.8 (4.6–16.9)

0.6097

DL,_CO, %pred

63.2 (43.5–125.4)

60.4 (26.9–74.4)

64.7 (29.0–109.4)

0.2751