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 mobility | Mobility measures where higher values represent better mobility | |||||
|---|---|---|---|---|---|---|
| BASMI linear | Tragus-to-wall distance | Lateral spinal flexion | Cervical rotation | Anterior lumbar flexion | Maximal intermalleolar distance | |
| Age | 0.02 (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-CRP | 0.21 (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 score | 0.02 (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-hips | 0.65 (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.