Table 1 Baseline demographics, laboratory data, and autoantibody profiles between MCTD-PAH and MCTD-non-PAH patients

Demographics

Sex [F/M, n (%)]

44 (95.7)/2 (4.4)

69 (94.5)/4 (5.5)

0.000

> 0.999

Age at MCTD onset (years, \(\bar x\)±s)

35.1 ± 12.8

36.5 ± 11.8

-0.603

0.547

Age at MCTD diagnosis (years, \(\overline{ x}\)±s)

37.8 ± 13.4

39.8 ± 12.2

-0.831

0.408

Age at PAH onset

(years, \(\bar x\)±s)

38.9 ± 13.4

Age at PAH diagnosis (years, \(\bar x\)±s)

39.9 ± 13.7

Height [m, M (P25-P75)]

1.61 (1.58–1.64)

1.61 (1.58–1.63)

-0.008

0.993

Weight (kg, \(\bar x\)±s)

60.76 ± 4.17

59.43 ± 3.50

1.874

0.063

BMI (kg/m², \(\bar x\)±s)

23.49 ± 1.49

22.99 ± 1.32

1.875

0.064

BSA (m², \(\bar x\)±s)

1.72 ± 0.06

1.71 ± 0.05

1.545

0.125

Clinical manifestations [n(%)]

SLEDAI-2 K

Activity

-0.052

0.958

Almost inactive

20

31

Mild

15

25

Moderate

8

12

Severe

3

5

SLEDAI-2 K scores

5.00 (1.00-9.25)

5.00 (4.00–9.00)

-0.907

0.364

Raynaud’s phenomenon

42 (91.3)

67 (91.8)

0.000

> 0.999

Sclerodactyly

15 (32.6)

17 (23.3)

1.247

0.264

Serositis

29 (63.0)

20 (27.4)

14.803

< 0.001

Limbs edema

8 (17.4)

7 (9.6)

1.559

0.212

Fatigue

26 (56.5)

36 (49.3)

0.587

0.443

Arthralgia

31 (67.4)

43 (58.9)

0.864

0.353

Chest tightness

35 (76.1)

24 (32.9)

21.076

< 0.001

Laboratory profiles

WBC (×10⁹/L, \(\bar x\)±s)

5.9 ± 2.8

7.6 ± 8.0

-1.426

0.156

RBC [×10¹²/L, M (P25-P75)]

4.3(3.8–4.8)

4.3(3.8–4.5)

-0.669

0.504

PLT (×10⁹/L, \(\bar x\)±s)

185.0 ± 84.9

206.7 ± 101.8

-1.207

0.230

HGB (g/L, \(\bar x\)±s)

124.6 ± 11.5

124.5 ± 12.1

0.079

0.937

MCV (fL, \(\bar x\)±s)

87.1 ± 3.3

86.4 ± 3.3

1.260

0.210

RDW [%, \(\bar x\)±s]

18.2 ± 3.4

13.8 ± 1.7

8.174

< 0.001

UA (µmol/L, \(\bar x\)±s)

320.5 ± 132.1

270.8 ± 97.9

2.200

0.031

CRP [mg/L, M (P25-P75)]

4.2 (2.5–11.3)

4.1 (2.5–8.9)

-0.612

0.541

ESR [mm/hr, M (P25-P75)]

29.5 (13.5–55.0)

29.0 (12.0-43.5)

-0.972

0.331

TSH [mU/L, M (P25-P75)]

2.6 (1.1–4.9)

1.3 (0.8–2.7)

-2.423

0.015

FT3 (pmol/L, \(\bar x\)±s)

3.0 ± 1.2

3.5 ± 1.0

-3.130

0.002

FT (pmol/L, \(\bar x\)±s)

14.9 ± 3.3

15.4 ± 3.0

-0.887

0.377

C3 (g/L, \(\bar x\)±s)

0.9 ± 0.3

1.0 ± 0.3

-1.648

0.102

C4 (g/L, \(\bar x\)±s)

0.2 ± 0.1

0.4 ± 0.8

-1.852

0.067

IgA [g/L, M (P25-P75)]

2.1 (1.5–3.3)

2.7 (2.0-3.4)

-1.839

0.066

IgG [g/L, M (P25-P75)]

17.0(12.1–27.5)

16.7 (13.1–20.0)

-0.854

0.393

IgM (g/L, \(\bar x\)±s)

1.3 ± 0.7

1.4 ± 0.9

-0.534

0.594

D-Dimer [mg/L, M (P25-P75)]

0.5 (0.2–1.4)

0.5 (0.3–0.8)

-1.561

0.118

Fg [g/L, M (P25-P75)]

2.6 (2.3–2.9)

2.6 (2.3-3.0)

-0.014

0.989

PT [s, M (P25-P75)]

18.5 (17.5–19.5)

18.9 (18.4–19.6)

-1.177

0.239

APTT (s, \(\bar x\)±s)

27.8 ± 4.9

28.3 ± 5.0

-0.526

0.600

Autoantibody profiles [positive number, n(%)]

Nuclear speckled

38 (82.6)

54 (74.0)

1.200

0.273

Nuclear homogeneous

1 (2.2)

1 (1.4)

—

1.00

Nuclear membrane

1 (2.2)

1 (1.4)

—

1.00

Nucleolar

1 (2.2)

1 (1.4)

—

1.00

Nuclear centromeric

1 (2.2)

4 (5.5)

0.165

0.685

Cytoplasmic

7 (15.2)

12 (16.4)

0.031

0.859

U1-RNP

35 (76.1)

48 (65.8)

1.428

0.232

Sm

3 (6.5)

6 (8.2)

—

1.00

SS-A

14 (30.4)

13 (17.8)

2.565

0.109

RO52

10 (21.7)

12 (16.4)

0.526

0.468

SS-B

5 (10.9)

3 (4.1)

1.120

0.290

SCL70

1 (2.2)

1 (1.4)

—

1.00

Jo-1

1 (2.2)

2 (2.7)

—

1.00

dsDNA

1 (2.2)

1 (1.4)

—

1.00