Relationship between baseline BMD and 2-year syndesmophyte formation as reported by at least one of the readers (secondary analysis)
| Variables | New radiographic syndesmophyte formation according to reader 1 or reader 2 | |
|---|---|---|
| Univariable analysis—adjOR (95% CI) | Multivariable analysis—adjOR (95% CI) | |
| BMD (g/cm2) | 0.35 (0.04, 2.89) | 0.26 (0.03, 2.63) |
| Age (years) | 1.05 (1.01, 1.08)* | 1.04 (1.00, 1.09)* |
| Gender (male) | 1.99 (0.79, 5.06) | 1.42 (0.50, 4.01) |
| Disease duration (years) | 1.03 (0.99, 1.07) | 1.00 (0.96, 1.05) |
| ASDAS | 1.29 (0.84, 1.98) | 1.09 (0.63, 1.87) |
| HLA-B27 | 0.58 (0.17, 1.93) | 0.54 (0.15, 1.89) |
| Treatment with NSAIDs | 1.16 (0.38, 3.53) | 0.82 (0.21, 3.13) |
| Treatment with infliximab | 1.01 (0.40, 2.56) | 1.11 (0.45, 2.69) |
| Presence of MRI VCI at baseline† | 3.80 (1.92, 7.55)* | 4.32 (1.95, 9.60)* |
| Presence of MRI VCFD at baseline† | 1.50 (0.74, 3.01) | 1.23 (0.60, 2.54) |
| Presence of syndesmophytes at baseline†,‡ | 4.10 (1.48, 11.35)* | 3.14 (1.14, 8.66)* |
| New radiographic syndesmophyte formation according to reader 1 | ||
| Variables | Univariable analysis—adjOR (95% CI) | Multivariable analysis—adjOR (95% CI) |
| BMD (g/cm2) | 0.10 (0.00, 1.34) | 0.07 (0.00, 1.56) |
| Age (years) | 1.04 (1.00, 1.09)* | 1.05 (1.00, 1.10) |
| Gender (male) | 1.63 (0.57, 4.71) | 1.17 (0.36, 3.86) |
| Disease duration (years) | 1.03 (0.98, 1.08) | 1.01 (0.96, 1.06) |
| ASDAS | 1.27 (0.75, 2.13) | 1.00 (0.49, 2.02) |
| HLA-B27 | 0.45 (0.13, 1.52) | 0.39 (0.10, 1.52) |
| Treatment with NSAIDs | 1.60 (0.48, 5.30) | 1.27 (0.27, 5.93) |
| Treatment with infliximab | 1.30 (0.39, 4.36) | 1.24 (0.40, 3.83) |
| Presence of MRI VCI at baseline† | 4.05 (1.58, 10.38)* | 5.84 (2.21, 15.47)* |
| Presence of MRI VCFD at baseline† | 1.24 (0.50, 3.06) | 1.10 (0.41, 2.90) |
| Presence of syndesmophytes at baseline†,‡ | 6.39 (1.87, 21.84)* | 5.97 (1.67, 21.30)* |
| New radiographic syndesmophyte formation according to reader 2 | ||
| Variables | Univariable analysis—adjOR (95% CI) | Multivariable analysis—adjOR (95% CI) |
| BMD (g/cm2) | 0.66 (0.18, 10.29) | 0.63 (0.13, 13.68) |
| Age (years) | 1.05 (1.00, 1.10)* | 1.04 (0.98, 1.10) |
| Gender (male) | 2.26 (0.64, 7.95) | 1.38 (0.28, 6.84) |
| Disease duration (years) | 1.05 (1.00, 1.09)* | 1.02 (0.97, 1.08) |
| ASDAS | 1.53 (0.87, 2.67) | 1.63 (0.85, 3.12) |
| HLA-B27 | 0.35 (0.09, 1.36) | 0.26 (0.06, 1.23) |
| Treatment with NSAIDs | 0.71 (0.18, 2.70) | 0.42 (0.09, 1.86) |
| Treatment with infliximab | 0.91 (0.29, 2.83) | 1.13 (0.38, 3.38) |
| Presence of MRI VCI at baseline† | 1.65 (1.04, 6.76)* | 2.62 (0.90, 7.63) |
| Presence of MRI VCFD at baseline† | 1.17 (0.50, 2.76) | 1.02 (0.46, 2.27) |
| Presence of syndesmophytes at baseline†,‡ | 3.07 (0.83, 11.40) | 2.88 (0.66, 12.70) |
adjOR, adjusted OR; ASDAS, Ankylosing Spondylitis Disease Activity Score; BMD, Bone mineral density; CI, Confidence Interval; GEE, Generalised estimated equations; NSAIDs, Nonsteroidal anti-inflammatory drugs; VCFD, Vertebral corner fat deposition; VCI, Vertebral corner inflammation.
†Radiographic and MRI case definitions aiming at specificity were used (absolute agreement of the readers).
‡Syndesmophytes anywhere in the spine defined as a patient with at least one vertebral corner that received a modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) of ≥2, according to the absolute agreement of readers. *p<0.05.