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Table 1 Characteristics of the study population

From: Gut dysbiosis associated with worse disease activity and physical function in axial spondyloarthritis

 

All axSpA

(Nr-axSpA+AS)

Nr-axSpA

AS

Controls

n=132

n=44

n=88

n=46

Male sex, n (%)

72 (55%)

17 (39%)

55 (63%) ‡

23 (50%)

Age, years

53 (13)

48 (12)

55 (13) ‡

51 (14)

BMI, kg/m2

27 (4.3)

27 (4.2)

27 (4.3)‡

25 (3.3) ‡‡

Smoking status

 Never smoker, n (%)

89 (67%)

35 (80%)

54 (61%)

32 (71%)

 Quit smoking >6 months ago, n (%)

31 (24%)

7 (16%)

24 (27%)

11 (24%)

 Intermittent smoker or quit <6 months ago, n (%)

5 (3.8%)

1 (2.3%)

4 (4.5%)

0

 Every day smoker, n (%)

7 (5.3%)

1 (2.3%)

6 (6.8%)

2 (4.4%)

Family history of SpA, n (%)

58 (44%)

17 (39%)

41 (47%)

 

Symptom duration, years

26 (14)

21 (11)

28 (14) ‡

 

HLA-B27 positive, n (%)

114 (87%)

41 (93%)

73 (84%)

 

Back pain ≥3 months:

 With onset <45 years, n (%)

127 (96%)

44 (100%)

83 (94%)

 

 Improved by exercise and not relieved by rest, n (%)

103 (79%)

33 (75%)

70 (81%)

 

Inflammatory back pain (ASAS definition), n (%)

112 (85%)

37 (84%)

75 (85%)

 

Sagittal lumbar flexion (Modified Schober’s test), cm

4.2 (1.6)

4.2 (1.2)

4.2 (1.8)

 

Lateral lumbar flexion, cma

14 (4.9)

15 (4.9)

13 (4.8) ‡

 

Chest expansion, cm

4.8 (1.8)

5.0 (1.9)

4.7 (1.7)

 

Sacroiliitis on plain X-ray, n (%)

88 (67%)

0 (0%)

88 (100%) ‡

 

SI joint MRI available, n (%)

65 (49%)

25 (57%)

40 (45%)

 

SI joint bone marrow oedema on MRI, n (%) b

32 (49%)

9 (36%)

23 (58%)

 

Good response of back pain to NSAID, n (%)

103 (78%)

33 (75%)

70 (80%)

 

Elevated CRP in the presence of back pain, n (%)

82 (62%)

25 (57%)

57 (65%)

 

Peripheral arthritis, n (%)

68 (52%)

26 (59%)

42 (48%)

 

Dactylitis, n (%)

15 (11%)

9 (21%)

6 (6.8%) ‡

 

Heel enthesitis, n (%)

57 (43%)

22 (50%)

35 (40%)

 

History of uveitis, n (%)

46 (35%)

11 (25%)

35 (40%)

 

Skin and/or nail psoriasis, n (%)

8 (6.1%)

3 (6.8%)

5 (5.7%)

 

IBD, n (%)

0 (0%)

0 (0%)

0 (0%)

0 (0%)

F-calprotectin, mg/kg

 Mean (SD)

74 (131)

48 (55)

87 (155)

 

 Median (IQR)

33 (60)

29 (39)

39 (65)

 

Elevated F-calprotectin ≥50 mg/kg, n (%)

46 (35%)

12 (28%)

34 (39%)

 

IBS symptoms, n (%)c

43 (33%)

15 (34%)

28 (32%)

 

ASDAS-CRP

1.8 (0.9)

1.9 (0.9)

1.8 (0.9)

 

BASDAI

3.1 (2.2)

3.3 (1.9)

3.0 (2.4)

 

EvalGlobal, 0–4, median (IQR)d

1 (0-1)

1 (0-1)

1 (0–1)

 

CRP, mg/l

3.7 (5.3)

2.3 (2.4)

4.3 (6.1)

 

BASFI

2.0 (2.1)

2.0 (1.7)

2.1 (2.2)

 

BASMI

3.0 (1.4)

2.5 (1.1)

3.2 (1.5) ‡

 

VAS pain, cm

3.3 (2.5)

3.4 (2.2)

3.2 (2.7)

 

ASAS 3-month NSAID score

37 (44)

36 (44)

37 (44)

 

Use of proton-pump inhibitors last 3 months, n (%)

53 (40%)

19 (43%)

34 (39%)

 

Ongoing csDMARD, n (%)

24 (18%)

9 (20%)

15 (17%)

 

 Methotrexate, n (%)

14 (10.6%)

4 (9.1%)

10 (11.4%)

 

 Sulfasalazine, n (%)

8 (6.1%)

3 (6.8%)

5 (5.7%)

 

 Other csDMARD, n (%)

2 (1.5%)

2 (4.5%)

0 (0%)

 

Ongoing bDMARD, n (%)

56 (42%)

19 (43%)

37 (42%)

 

 Adalimumab, n (%)

10 (7.6%)

2 (4.5%)

8 (9.1%)

 

 Certolizumab pegol, n (%)

11 (8.3%)

7 (15.9%)

4 (4.5%)‡

 

 Etanercept, n (%)

19 (14.4%)

5 (11.4%)

14 (15.9%)

 

 Golimumab, n (%)

5 (3.8%)

2 (4.5%)

3 (3.4%)

 

 Infliximab, n (%)

9 (6.8%)

2 (4.5%)

7 (8.0%)

 

 Secukinumab, n (%)

2 (1.5%)

1 (2.3%)

1 (1.1%)

 
  1. Mean (SD) if not otherwise stated. aMean of right and left lateral lumbar flexion. bPrevious or current SI joint bone marrow oedema according to the ASAS definition. cMeeting the ROME III criteria for IBS. dLikert scale 0–4, corresponding to Remission/Low/Medium/High/Maximal. ‡p<0.05 for between-group difference between nr-axSpA and AS by chi2-test/Fisher´s Exact test or Mann-Whitney U test, as appropriate. ‡‡p<0.05 for between-group difference between axSpA (nr-axSpA and AS combined) and controls by Mann-Whitney U test. Missing data, n (%): Symptom duration 1 (0.8%); HLA-B27 1 (0.8%); back pain improved by exercise but not by rest 1 (0.8%); chest expansion 1 (0.8%); F-calprotectin 2 (1.5%); IBS symptoms 1 (0.8%); ASDAS-CRP 16 (12%); BASDAI 7 (5.3%), EvalGlobal 5 (3.8%); CRP 15 (11%); BASFI 9 (6.8%); BASMI 2 (1.5%); VAS pain 2 (1.5%); Smoking, controls 1 (2.2%). AS ankylosing spondylitis, ASDAS-CRP ankylosing spondylitis disease activity score using CRP, ASAS Assessment of SpondyloArthritis international Society, AxSpA axial spondyloarthritis, BASDAI Bath ankylosing spondylitis disease activity index, BASFI Bath ankylosing spondylitis functional index, BASMI Bath ankylosing spondylitis metrology index, bDMARD biologic disease-modifying anti-rheumatic drug, CRP C-reactive protein, csDMARD conventional synthetic disease-modifying anti-rheumatic drug, EvalGlobal evaluator’s global assessment of disease activity, HLA human leukocyte antigen, IBD inflammatory bowel disease, IBS irritable bowel syndrome, IQR interquartile range, MRI magnetic resonance imaging, nr-axSpA non-radiographic axial spondyloarthritis, NSAID non-steroidal anti-inflammatory drug, SD standard deviation, SI sacroiliac, SpA spondyloarthritis, VAS visual analog scale
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Arthritis Research & Therapy

ISSN: 1478-6362

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