Table 2

Impact of male sex on spinal radiographic progression in axSpA

ModelVariable(A) Progression defined as ≥2 mSASSS units in 2 years(B) Progression defined as ≥1 syndesmophyte in 2 years
OR95% CIP valueOR95% CIP value
Main modelMale sex (total effect)3.411.87 to 6.21<0.0012.911.67 to 5.09<0.001
TNFi use prior to X-ray interval0.740.48 to 1.140.170.610.40 to 0.930.02
Length of the X-ray interval (+1 year)1.550.82 to 2.960.181.520.85 to 2.700.16
Large modelMale sex (direct effect)1.971.04 to 3.710.041.540.82 to 2.900.18
TNFi use prior to X-ray interval0.600.34 to 1.050.080.580.34 to 0.970.04
Length of the X-ray interval (+1 year)1.780.92 to 3.450.091.991.04 to 3.780.04
mSASSS at start of X-ray interval1.071.05 to 1.09<0.001
Syndesmophytes at start of X-ray interval8.854.92 to 15.9<0.001
ASDAS (+1 unit)1.401.05 to 1.880.021.280.97 to 1.690.09
HLA-B270.850.41 to 1.720.640.780.38 to 1.510.43
Symptom duration (+1 year)1.151.01 to 1.300.031.100.98 to 1.240.12
Current smoking1.010.57 to 1.790.980.880.51 to 1.500.63
No of exercise sessions per week (+1 session)0.970.86 to 1.080.540.930.83 to 1.030.16
Current peripheral arthritis0.800.45 to 1.420.450.780.43 to 1.410.41
NSAIDs use at start of X-ray interval0.690.34 to 1.380.291.010.49 to 2.080.98
BMI 25–30 (reference BMI<25)1.600.93 to 2.770.091.010.61 to 1.680.97
BMI>30 (reference BMI<25)1.630.80 to 3.320.181.180.57 to 2.420.65
  • 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.