Table 1 Characteristics of the patients with AxSpA included in the study

Number of cases (n)

186

4

8

73

72

29

NA

4

10

74

72

26

NA

Age (years)

26.4 ± 8.7

25.3 ± 5.4

29.4 ± 10.7

24.9 ± 8.7

27. 6 ± 8.3

26.5 ± 9.2

0.138

25.3 ± 5.4

25.7 ± 9.4

25.0 ± 8.6

27.9 ± 8.5

26.7 ± 9.4

0.133

Male/female (n)

143/43

3/1

6/2

55/18

54/18

25/4

0.763

3/1

7/3

57/17

53/19

23/3

0.564

AxSpA duration (years)

4.3 ± 4.0

0.8 ± 0.3

4.4 ± 2.5

3.1 ± 3.1

4.8 ± 3.7

6.9 ± 5.6

<0.001

0.8 ± 0.3

4.5 ± 2.9

2.8 ± 2.2

5.1 ± 4.3

7.0 ± 5.5

<0.001

HLA-B27 (+/-) (n)

164/22

3/1

6/2

68/8

65/7

25/4

0.725

3/1

9/1

64/10

66/6

22/4

0.741

ESR (mm/h)

25.1 ± 22.1

9.5 ± 10.6

10.1 ± 8.9

20.2 ± 16.5

29.1 ± 24.8

33.7 ± 25.7

0.002

9.5 ± 10.6

23.8 ± 20.1

19.2 ± 17.2

28.3 ± 23.9

35.8 ± 26.3

0.007

CRP (mg/l)

14.3 ± 17.5

1.0 ± 0.5

3.1 ± 2.4

9.2 ± 13.1

16. 6 ± 17.2

26.0 ± 23.4

<0.001

1.0 ± 0.5

9.4 ± 15.6

9.9 ± 14.3

15.1 ± 15.9

28.1 ± 23.8

<0.001

Total back pain^#

4.9 ± 2.8

1.3 ± 0.5

1.9 ± 1.4

4.5 ± 2.6

5.4 ± 2.6

6.3 ± 2.8

<0.001

1.3 ± 0.5

3.6 ± 3.2

4.5 ± 2.6

5.2 ± 2.6

6.6 ± 2.8

<0.001

PGA of disease activity^#

5.6 ± 3.0

2.5 ± 1.9

2.5 ± 1.8

5.3 ± 2.8

5.9 ± 2.9

7.0 ± 2.9

<0.001

2.5 ± 1.9

4.4 ± 3.7

5.1 ± 2.8

5.9 ± 2.7

7.3 ± 3.0

0.002

Pain and swelling of peripheral arthritis^#

0.2 ± 0.5

NA

0.3 ± 0.4

0.2 ± 0.4

0.3 ± 0.5

0.4 ± 0.6

0.249

NA

0.2 ± 0.4

0.2 ± 0.4

0.3 ± 0.5

0.4 ± 0.6

0.227

Duration of morning stiffness^#

5.4 ± 2.8

2.8 ± 1.0

2.0 ± 1.3

5.1 ± 2.7

5.8 ± 2.6

6.4 ± 2.9

<0.001

2.8 ± 1.0

4.0 ± 3.6

4.9 ± 2.6

5.8 ± 2.5

6.7 ± 2.9

0.003

ASDAS (scores)

2.7 ± 1.1

1.0 ± 0.2

1.4 ± 0.4

2.4 ± 1.3

3.0 ± 1.3

3.5 ± 1.5

<0.001

1.0 ± 0.2

2.1 ± 1.6

2.4 ± 1.3

2.9 ± 1.3

3.6 ± 1.6

<0.001

BASFI (scores)

4.3 ± 1.1

1.9 ± 0.8

2.5 ± 0.9

4.0 ± 1.0

4.6 ± 0.7

4.9 ± 0.8

<0.001

1.9 ± 0.8

3.1 ± 1.5

4.1 ± 1.0

4.5 ± 0.8

4.9 ± 0.8

<0.001

Use of NSAIDs (ever/never) (n)

169/17

0/4

8/0

68/5

67/5

26/3

<0.001

0/4

10/0

70/4

66/6

23/3

<0.001

Use of DMARDs (≥3/<3 months) (n)

169/17

1/3

6/2

69/4

68/4

25/4

0.005

1/3

8/2

70/4

67/5

23/3

0.010

  > 12 months

28

0

4

18

4

2

<0.001

0

5

15

6

2

<0.001

  ≤ 12 months

42

1

3

21

15

2

1

3

24

12

2

  ≤ 6 months

59

2

1

16

30

10

2

0

18

32

7

 Never

57

1

0

18

23

15

1

2

17

22

15

Serum uric acid (μmol/L)

362.7 ± 107.9

284.0 ± 95.3

345.1 ± 77.0

361.9 ± 105.5

366.0 ± 117.7

372.2 ± 97.8

0.593

284.0 ± 95.3

325.6 ± 103.5

362.3 ± 101.9

372.4 ± 118.8

363.3 ± 94.6

0.499

 Sacroiliac joint

111/261^$

0/4

0/8

14/59

29/43

14/15

<0.001

0/4

1/9

13/61

28/44

12/44

0.002

 Hip joint

75/111

1/3

4/4

33/40

28/44

9/20

0.632

1/3

6/4

32/42

29/43

7/19

0.369

 Pubic symphysis

63/123

0/4

3/5

25/48

28/44

7/22

0.244

0/4

4/6

25/49

29/43

5/21

0.112

 Sacroiliac joint

0.29 ± 0.99^$

NA

NA

0.10 ± 0.30

0.31 ± 0.69

0.75 ± 1.72

0.001

NA

0.01 ± 0.01

0.10 ± 0.32

0.41 ± 1.19

0.83 ± 2.11

0.005

 Total volume at pelvis

4.37 ± 8.46

0.02 ± 0.03

0.63 ± 0.99

4.36 ± 8.01

4.92 ± 10.03

4.62 ± 6.72

0.077

0.02 ± 0.03

2.15 ± 4.16

4.00 ± 7.73

5.51 ± 10.37

3.78 ± 5.91

0.118