Table 2.
Impact of male sex on spinal radiographic progression in axSpA
| Model | Variable | (A) Progression defined as ≥2 mSASSS units in 2 years | (B) Progression defined as ≥1 syndesmophyte in 2 years | ||||
| OR | 95% CI | P value | OR | 95% CI | P value | ||
| Main model | Male sex (total effect) | 3.41 | 1.87 to 6.21 | <0.001 | 2.91 | 1.67 to 5.09 | <0.001 |
| TNFi use prior to X-ray interval | 0.74 | 0.48 to 1.14 | 0.17 | 0.61 | 0.40 to 0.93 | 0.02 | |
| Length of the X-ray interval (+1 year) | 1.55 | 0.82 to 2.96 | 0.18 | 1.52 | 0.85 to 2.70 | 0.16 | |
| Large model | Male sex (direct effect) | 1.97 | 1.04 to 3.71 | 0.04 | 1.54 | 0.82 to 2.90 | 0.18 |
| TNFi use prior to X-ray interval | 0.60 | 0.34 to 1.05 | 0.08 | 0.58 | 0.34 to 0.97 | 0.04 | |
| Length of the X-ray interval (+1 year) | 1.78 | 0.92 to 3.45 | 0.09 | 1.99 | 1.04 to 3.78 | 0.04 | |
| mSASSS at start of X-ray interval | 1.07 | 1.05 to 1.09 | <0.001 | ||||
| Syndesmophytes at start of X-ray interval | 8.85 | 4.92 to 15.9 | <0.001 | ||||
| ASDAS (+1 unit) | 1.40 | 1.05 to 1.88 | 0.02 | 1.28 | 0.97 to 1.69 | 0.09 | |
| HLA-B27 | 0.85 | 0.41 to 1.72 | 0.64 | 0.78 | 0.38 to 1.51 | 0.43 | |
| Symptom duration (+1 year) | 1.15 | 1.01 to 1.30 | 0.03 | 1.10 | 0.98 to 1.24 | 0.12 | |
| Current smoking | 1.01 | 0.57 to 1.79 | 0.98 | 0.88 | 0.51 to 1.50 | 0.63 | |
| No of exercise sessions per week (+1 session) | 0.97 | 0.86 to 1.08 | 0.54 | 0.93 | 0.83 to 1.03 | 0.16 | |
| Current peripheral arthritis | 0.80 | 0.45 to 1.42 | 0.45 | 0.78 | 0.43 to 1.41 | 0.41 | |
| NSAIDs use at start of X-ray interval | 0.69 | 0.34 to 1.38 | 0.29 | 1.01 | 0.49 to 2.08 | 0.98 | |
| BMI 25–30 (reference BMI<25) | 1.60 | 0.93 to 2.77 | 0.09 | 1.01 | 0.61 to 1.68 | 0.97 | |
| BMI>30 (reference BMI<25) | 1.63 | 0.80 to 3.32 | 0.18 | 1.18 | 0.57 to 2.42 | 0.65 | |
Results from different multivariable models with spinal radiographic progression defined as either an increase of ≥2 mSASSS units in 2 years (A) or as the formation of ≥1 new syndesmophyte in 2 years (B), after multiple imputation of missing covariate data. Analyses performed in 724 radiographic intervals from 505 axSpA patients (108 progression events (88 in men, 20 in women) in A and 109 progression events (88 in men and 21 in women) in B.
ASDAS, Ankylosing Spondylitis Disease Activity Score; axSpA, axial spondyloarthritis; BMI, body mass index; HLA-B27, human leucocyte antigen B27; mSASSS, Modified Stoke Ankylosing Spondylitis Spinal Score; NSAID, non-steroidal anti-rheumatic drug; TNFi, tumour necrosis factor inhibitor.