Table 3.
Univariate and multivariate linear regressions using BASFI and BASMI as dependent variables.
| Univariate linear regressions | Multivariate linear regressions | |||||
|---|---|---|---|---|---|---|
| Standard coefficient (B) | Regression coefficient (95% CI) | P value | Standard coefficient (B) | Regression coefficient (95% CI) | P value | |
| BASFI | (n = 389) | |||||
| Axial SpA with late onset (n = 447) | 0.13 | 0.82 (0.21; 1.42) | 0.01 | –0.02 | –0.12 (–0.66; 0.43) | 0.68 |
| Age (n = 447) | 0.20 | 0.03 (0.02; 0.05) | <0.001 | 0.06 | 0.01 (–0.01; 0.03) | 0.24 |
| Male gender (n = 447) | 0.01 | 0.05 (–0.39; 0.50) | 0.82 | |||
| Chinese ethnicity (n = 447) | 0.04 | 0.79 (–1.11; 2.69) | 0.41 | |||
| Body weight (n = 394) | 0.06 | 0.01 (–0.01; 0.03) | 0.20 | |||
| Smoking status (n = 444) | 0.10 | 0.54 (0.04; 1.04) | 0.03 | 0.35 | 0.19 (–0.21; 0.59) | 0.35 |
| Regular alcohol use (n = 439) | 0.11 | 0.88 (0.12; 1.64) | 0.02 | 0.03 | 0.24 (–0.36; 0.85) | 0.43 |
| Family history of SpA (n = 433) | 0.04 | 0.20 (–0.33; 0.73) | 0.47 | |||
| HLA-B27 positivity (n = 427) | –0.12 | –0.75 (–1.32; –0.18) | 0.01 | –0.05 | –0.28 (–0.70; 0.15) | 0.20 |
| BASMI (n = 442) | 0.47 | 0.63 (0.52; 0.74) | <0.001 | 0.30 | 0.41 (0.27; 0.55) | <0.001 |
| Radiological AS (n = 431) | 0.13 | 0.61 (0.17; 1.06) | 0.01 | –0.04 | –0.17 (–0.53; 0.19) | 0.36 |
| ASDAS-CRP (n = 437) | 0.67 | 1.82 (1.63; 2.02) | <0.001 | 0.58 | 1.58 (1.38; 1.78) | <0.001 |
| mSASSS (N = 416) | 0.23 | 0.03 (0.02; 0.04) | <0.001 | –0.06 | –0.01 (–0.02; 0.01) | 0.22 |
| BASMI | ||||||
| Axial SpA with late onset (n = 446) | 0.21 | 0.98 (0.54; 1.41) | <0.001 | –0.01 | –0.06 (–0.44; 0.33) | 0.77 |
| Age (n = 446) | 0.49 | 0.06 (0.05; 0.07) | <0.001 | 0.24 | 0.30 (0.02; 0.04) | <0.001 |
| Male gender (n = 446) | 0.08 | 0.27 (–0.05; 0.60) | 0.102 | |||
| Chinese ethnicity (n = 446) | 0.001 | 0.02 (–1.38; 1.41) | 0.98 | |||
| Body weight (n = 394) | –0.03 | –0.003 (–0.02; 0.01) | 0.62 | |||
| Smoking status (n = 444) | 0.14 | 0.55 (0.19; 0.92) | 0.003 | 0.004 | 0.02 (–0.27; 0.30) | 0.91 |
| Regular alcohol use (n = 439) | 0.08 | 0.48 (–0.07; 1.03) | 0.08 | –0.04 | –0.22 (–0.65; 0.21) | 0.32 |
| Family history of SpA (n = 433) | 0.02 | 0.06 (–0.33; 0.46) | 0.75 | |||
| HLA-B27 positivity (n = 426) | –0.07 | –0.31 (–0.73; 0.11) | 0.14 | |||
| ASDAS-CRP (n = 434) | 0.29 | 0.59 (0.41; 0.77) | <0.001 | 0.20 | 0.40 (0.26; 0.54) | <0.001 |
| mSASSS (n = 416) | 0.66 | 0.06 (0.06; 0.07) | <0.001 | 0.50 | 0.05 (0.04; 0.06) | <0.001 |
| Radiological AS (n = 431) | 0.32 | 1.12 (0.81; 1.43) | <0.001 | 0.14 | 0.50 (0.25; 0.75) | <0.001 |
AS = ankylosing spondylitis, ASDAS-CRP = Ankylosing Spondylitis Disease Activity Score based on CRP, BASFI = Bath Ankylosing Spondylitis Functional Index, BASMI = Bath Ankylosing Spondylitis Metrology Index, CI = confidence interval, HLA = human leukocyte antigen, mSASSS = modified Stoke Ankylosing Spondylitis Spinal Score, n = number, SpA = spondyloarthritis.