Table 2

Multivariable GEE results (adjB; 95% CI) presenting independent associations between BASMI linear (or its components) and clinical and demographic variables

Mobility measures where higher values represent worse mobilityMobility measures where higher values represent better mobility
BASMI linearTragus-to-wall distanceLateral spinal flexionCervical rotationAnterior lumbar flexionMaximal intermalleolar distance
Age0.02
(0.01 to 0.03)
−0.09
(−0.13 to −0.04)
−0.24
(−0.38 to −0.10)
−0.35
(−0.49 to −0.20)
Male gender*0.87
(0.56 to 1.17)
1.61
(0.77 to 2.46)
*5.14
(2.83 to 7.46)
Education†****5.96
(3.47 to 8.46)
BMI−0.04
(−0.06 to −0.01)
0.04
(0.00 to 0.08)
0.07
(0.05 to 0.10)
HLA-B27 positive−0.24
(−0.41 to −0.08)
2.64
(0.08 to 5.19)
2.95
(0.44 to 5.45)
Symptom duration−0.28
(−0.43 to −0.13)
0.07
(0.03 to 0.11)
0.54
(0.26 to 0.82)
Currently employed*
Current arthritis−4.63
(−9.10 to −0.15)
*
ASDAS-CRP0.21
(0.15 to 0.28)
0.29
(0.07 to 0.42)
−0.59
(−0.94 to −0.24)
−2.11
(−3.26 to −0.96)
−0.14
(−0.24 to −0.04)
−1.96
(−2.50 to −1.41)
Enthesitis score0.02
(0.01 to 0.04)
−0.08
(−0.15 to 0.00)
−0.32
(−0.53 to −0.12)
−0.26
(−0.40 to −0.12)
mSASSS*0.15
(−0.11 to 0.41)‡
−0.26
(−0.83 to −0.23)
−0.87
(−1.85 to 0.11)‡
BASRI-hips0.65
(0.31 to 1.00)
§§§§
MRI inflammation score (spine)0.11
(0.04 to 0.19)
0.28
(0.07 to 0.49)
−0.53
(−0.83 to −0.23)
−0.90
(−1.76 to −0.05)
−0.09
(−0.16 to −0.02)
MRI inflammation score (SIJ)*
NSAID intake in the last 6 months*
cDMARD intake in the last 6 months*
  • *Statistically significant variables in the univariable analysis but excluded from the best-fit multivariable model;

  • †Education at baseline (university or equivalent).

  • ‡mSASSS was not significant in the multivariable model but included as it was found to be a contributory variable improving model-fit.

  • §BASRI-hips was only considered for BASMI linear and for maximal intermalleolar distance.

  • adjB, adjusted B; ASDAS-CRP, Ankylosing Spondylitis Disease Activity Score C reactive protein; BASMI, Bath Ankylosing Spondylitis Metrology Index; BASRI-hips, Bath Ankylosing Spondylitis Radiology Index for the hips; BMI, body mass index; cDMARD, conventional disease-modifying antirheumatic drugs; GEE, generalised estimating equations; HLA-B27, human leucocyte antigen B27; mSASSS, Modified Stoke Ankylosing Spondylitis Spinal Score; NSAID, nonsteroidal anti-inflammatory drugs; SIJ, sacroiliac joint.