Table 2.
Bone strength of AS with and without radiographic hip involvement.
| RHI-AS (n=177) | WORHI-AS (n=162) | Unadjusted | Adjusted for age and BMI | |||
|---|---|---|---|---|---|---|
| P | OR (95% CI) | P | OR (95% CI) | |||
| SI, median (Q1, Q3) | 77.9 (66, 85.7) | 80.3 (71.6, 89.4) | 0.015 | 0.984 (0.971, 0.997) | 0.017 | 0.982 (0.968, 0.997) |
| Z score | ||||||
| Median (Q1, Q3) | −1.5 (−2.5, −0.6) | −0.8 (−1.7,0.3) | <0.001 | 0.692 (0.592, 0.809) | 0.01 | 0.802 (0.679, 0.949) |
| ≤−2, n (%) | 66 (37.3) | 26 (16.0) | <0.001 | 3.110 (1.852, 5.223) | 0.026 | 1.891 (1.079, 3.313) |
| T score | ||||||
| Median (Q1, Q3) | −2.2 (−3.2, −1.5) | −1.8 (−2.6, −1) | 0.002 | 0.780 (0.667, 0.913) | 0.005 | 0.781 (0.658, 0.927) |
| ≤−2.5, n (%) | 76 (42.9) | 56 (34.6) | 0.115 | 1.424 (0.918, 2.211) | 0.115 | 1.478 (0.909, 2.404) |
SI – Stiffness index; RHI-AS – ankylosing spondylitis with radiographic hip involvement; WORHI-AS – ankylosing spondylitis without radiographic hip involvement.