Table 1 Basic characteristics of the rheumatoid arthritis patients

Demographic features

Age(years)

54.94 ± 10.92

59.19 ± 9.09**

61.97 ± 8.80***

64.38 ± 11.97***

62.47 ± 9.54***

Male, n(%)

33(24.44)

32(29.91)

20(21.98)

14(58.33)**

34(29.57)

BMI(kg/m²)

21.77 ± 3.41

21.96 ± 3.06

23.51 ± 3.92**

22.48 ± 3.57

23.30 ± 3.86**

Current/ever smoking, n(%)

16(11.85)

17(15.89)

12(13.19)

10(41.67)**

22(19.13)

RA associated clinical features

Duration of RA(years)

7.00(2.00,11.00)

7.00(1.00,15.00)

6.00(1.00,13.00)

5.00(2.00,10.00)

5.00(2.00,11.00)

Morning stiffness, n(%)

99(73.33)

80(74.77)

63(69.23)

16(66.67)

79(68.70)

Joint deformity, n(%)

50(37.04)

43(40.19)

31(34.07)

8(33.33)

39(33.91)

RF, IU/ml

82.80(18.00,268.00)

105.00(29.80,429.00)

125.00(22.40,491.00)

437.50(111.00,1077.25)***

144.00(23.70,541.00)*

Anti-CCP, RU/ml

83.60(16.70,200.00)

79.80(34.10,200.00)

81.90(12.60,200.00)

184.00(48.55,200.00)

99.10(18.70,200.00)

DAS28(CRP)

4.11 ± 1.50

4.21 ± 1.73

4.14 ± 1.64

3.73 ± 1.45

4.06 ± 1.61

DAS28(ESR)

4.67 ± 1.52

4.87 ± 1.72

4.78 ± 1.66

4.66 ± 1.46

4.76 ± 1.62

Respiratory manifestations

Cough, n(%)

0(0.00)

2(1.87)

5(5.49)*

15(62.50)***

20(17.39)***

Dyspnea, n(%)

1(0.74)

1(0.93)

3(3.30)

14(58.33)***

17(14.78)***

Velcro rale, n(%)

0(0.00)

0(0.00)

2(2.20)

13(54.17)***

15(13.04)***

Pulmonary function test

FVC%pred

92.00 ± 7.07

86.11 ± 9.18

81.33 ± 13.22

77.67 ± 20.05

80.11 ± 15.31

DlCO%pred

97.00 ± 18.39

74.22 ± 31.29

59.50 ± 18.22*

55.83 ± 18.08*

58.28 ± 17.72*

CT pattern

UIP

16(66.67)

NSIP

8(33.33)

Inflammatory markers

CRP, mg/l

15.30(3.49,43.30)

13.30(4.07,39.80)

15.20(4.93,57.00)

9.29(4.04,32.08)

14.50(4.48,46.90)

ESR, mm/h

40.00(19.00,74.00)

40.00(22.00,65.00)

44.00(25.00,81.00)

55.50(38.00,74.25)

45.00(26.00,80.00)

Pulmonary arterial pressure, mmHg

27.60 ± 5.30

28.91 ± 5.25

30.01 ± 6.81

33.10 ± 5.24*

30.64 ± 6.59*

Comorbidities

Hypertension, n(%)

26(19.26)

25(23.36)

27(29.67)

4(16.67)

31(26.96)

Diabetes, n(%)

11(8.15)

16(14.95)

12(13.19)

3(12.50)

15(13.04)

Osteoporosis, n(%)

48(35.56)

42(39.25)

53(58.24)**

12(50.00)

65(56.52)**

Osteopenia, n(%)

29(21.48)

28(26.17)

17(18.68)

6(25.00)

23(20.00)

Fragility fracture, n(%)

5(3.70)

7(6.54)

13(14.29)**

3(12.50)

16(13.91)**

Joint replacement, n(%)

6(4.44)

13(12.15)

4(4.40)

1(4.17)

5(4.35)

Medication

Corticosteroid, n(%)

45(33.33)

31(28.97)

32(35.16)

13(54.17)

45(39.13)

Immunosuppressant, n(%)

63(46.67)

49(45.79)

40(43.96)

16(66.67)

56(48.70)