Table 3 AS patients with normal pulmonary function versus patients with restrictive pattern

Age (yr), median (min, max)

46 (30,70)

57 (33,68)

0.015

Males, n (%)

66 (63)

21 (78)

0.218

Disease duration (yr)

22 (7,55)

27 (8,46)

0.054

Lifelong non-smokers, n (%)

53 (51)

15 (56)

0.799

FVC (liters), mean (SD)

4.3 (1.1)

2.8 (0.7)

< 0.001

FVC %

103.4 (12.8)

69.4 (6.6)

< 0.001

FEV1 (liters)

3.4 (0.9)

2.2 (0.5)

< 0.001

FEV1 %

96.6 (12.2)

68.6 (7.9)

< 0.001

PEF (liters/minute)

493.2 (119.9)

400.0 (101.3)

< 0.001

PEF %

100.0 (16.0)

85.5 (15.8)

< 0.001

FEV1/FVC %

77.4 (6.1)

79.4 (8.3)

0.158

ASDAS

2.8 (1.0)

3.1 (0.9)

0.140

BASDAI

4.1 (2.1)

4.3 (2.0)

0.709

BASFI

1.8 (0.8, 8.0)

2.9 (0.9, 10.0)

0.003

BASMI

2.9 (1.6)

5.4 (1.8)

< 0.001

Chest expansion (cm)

4.6 (2.1)

2.9 (1.8)

< 0.001

Lumbar flexion (cm)

4.3 (1.4)

2.4 (1.6)

< 0.001

Lumbar lateral flexion (cm)

14.4 (5.6)

7.6 (5.5)

< 0.001

TWD (cm)

11.8 (7.8, 43.5)

18.5 (10.5, 38.0)

< 0.001

CRP

3.0 (1.0, 57.0)

7.0 (1.0, 28.0)

0.063

ESR

15.0 (2.0, 83.0)

28.0 (1.0, 90.0)

0.006

VO₂peak

41.0 (7.2)

35.9 (8.9)

0.002

Anti-TNF-α-medication, n (%)

21 (20)

9 (33)

0.201