Table 1 Demographic and clinical features in IIM patients

Classification of the disease

Dermatomyositis, n (%)

81 (57.0)

21 (51.2)

60 (59.4)

0.273

Polymyositis, n (%)

14 (9.9)

5 (12.2)

9 (8.9)

Anti-synthetase syndrome, n (%)

33 (23.2)

13 (31.7)

20 (19.8)

Immune-mediated necrotizing myopathy, n (%)

14 (9.9)

2 (4.9)

12 (11.9)

Demographics

Age, median (IQR), years

55.0 (45.8–64.0)

61.0 (52.0–69.5)

52.0 (43.0–61.0)

< 0.001

Female gender, n (%)

102 (71.8)

29 (70.7)

73 (72.3)

0.853

Disease course, median (IQR), months

5.0 (2.8–12.0)

7 (2.5–24.0)

5.0 (2.5–12.0)

0.170

BMI, mean ± SD

23.7 ± 3.9

22.8 ± 4.0

24.0 ± 3.8

0.090

Clinical features

Fever, n (%)

38 (26.8)

13 (31.7)

25 (24.8)

0.396

muscle weakness, n (%)

52 (36.6)

17 (41.5)

35 (34.7)

0.445

Arthralgia, n (%)

45 (31.7)

10 (24.4)

35 (34.7)

0.234

Dysphagia, n (%)

8 (5.6)

2 (4.9)

6 (5.9)

0.803

Skin involvement, n (%)

85 (59.9)

26 (63.4)

59 (58.4)

0.582

Interstitial lung diseases, n (%)

83 (58.5)

29 (70.7)

54 (53.5)

0.058

Cardiovascular risk factors

Hypertension, n (%)

24 (16.9)

9 (22)

15 (14.9)

0.306

Diabetes mellitus, n (%)

10 (7.0)

2 (4.9)

8 (7.9)

0.521

Hyperlipemia, n (%)

18 (12.7)

5 (12.2)

13 (12.9)

0.913

smoke current, n (%)

16 (24.5)

3 (7.3)

13 (12.9)

0.343

Laboratory tests

WBC, median (IQR), *10^9/L

8.6 (6.1–11.5)

10.6 (6.5–12.8)

8.1 (6.0–11.0)

0.014

CRP, median (IQR), mg/L

3.0 (1.0–10.6)

5.0 (1.0–32.0)

3.0 (1.0–7.0)

0.047

ESR, median (IQR), mm/h

9.0 (5.8–24.0)

12.0 (6.0–28.5)

7.0 (5.0–19.0)

0.044

CK, median (IQR), IU/L

79.5 (50.0–175.3)

108.0 (62.0–453.5)

73.0 (48.0–160.5)

0.058

CK-MB, median (IQR), ng/mL

2.1 (0.8–9.1)

5.4 (2.3–36.4)

1.4 (0.7–6.0)

< 0.001

hs-cTnI, median (IQR), pg/mL

6.5 (2.6–32.0)

37.6 (17.0–109.1)

4.8 (2.3–10.0)

< 0.001

Mb, median (IQR), ng/mL

25.0 (14.3–90.2)

73.6(19.8–315.4)

22.6 (12.8–48.5)

0.001

NT-proBNP, median (IQR), pg/mL

129.1 (49.5–372.8)

419.7 (176.9–1609.5)

84.2 (41.5–183.0)

< 0.001

LDH, median (IQR), IU/L

254.0 (207.8–382.8)

334.0 (234.5–552.0)

240.0 (196.5–332.5)

0.001

AST, median (IQR), IU/L

30.0 (19.0–53.3)

42.0 (25.0–70.0)

27.0 (18.5–43.5)

0.022

ALT, median (IQR), IU/L

25.0 (14.0–59.3)

21.0 (14.0–57.0)

26.0 (14.0–59.5)

0.855

eGFR, mean ± SD, mL/min/1.73m2

99.4 ± 19.3

94.2 ± 20.9

101.5 ± 18.3

0.055

Disease activity measures

PhGA, median (IQR)

3.5 (2.8–4.5)

4.0 (3.0–5.2)

3.2 (2.4–4.0)

0.013

PGA, median (IQR)

4.5 (3.0–6.0)

4.5 (3.0–6.3)

4.5 (3.0–6.0)

0.483

HAQ, median (IQR)

0.4 (0–0.8)

0.5 (0.2–1.0)

0.3 (0–0.6)

0.04

MMT-8, median (IQR)

76.0 (70.8–78.0)

74.0 (70.0–80.0)

76.0 (72.0–78.0)

0.784

MDAAT, median (IQR)

2.0 (2.0–3.0)

3.0 (2.5–4.0)

2.0 (1.0–3.0)

< 0.001