Table 4.

Logistic regression analysis of syndesmophyte formation/radiographic progression adjusted by serum CRP levels and other patient and disease factors.

Variables	Syndesmophyte Formation^*
	Week 104		Week 208
	OR (95% CI)	p	OR (95% CI)	p
CRP at baseline, n = 290
Age, yrs	1.032 (1.004–1.061)	0.0227	1.035 (1.008–1.063)	0.0116
CRP at baseline	1.116 (0.977–1.275)	0.1072	1.155 (1.011–1.319)	0.0338
Disease duration, yrs	0.989 (0.954–1.026)	0.5471	0.998 (0.964–1.034)	0.9180
Male/female = 1/0	0.541 (0.289–1.012)	0.0544	0.544 (0.299–0.988)	0.0454
HLA-B27, positive/negative = 1/0	0.967 (0.443–2.114)	0.9337	0.973 (0.457–2.071)	0.9436
mSASSS at baseline	1.045 (1.026–1.064)	< 0.0001	1.031 (1.013–1.049)	0.0006
Smoking status, yes/no = 1/0	0.643 (0.374–1.105)	0.1099	0.598 (0.356–1.005)	0.0523
CRP at Week 14, n = 291
Age, yrs	1.026 (0.998–1.054)	0.0641	1.031 (1.004–1.059)	0.0246
CRP at Week 14	0.989 (0.776–1.261)	0.9292	1.105 (0.885–1.378)	0.3774
Disease duration, yrs	0.987 (0.951–1.023)	0.4702	0.992 (0.958–1.028)	0.6722
Male/female = 1/0	0.554 (0.295–1.038)	0.0653	0.563 (0.310–1.023)	0.0592
HLA-B27, positive/negative = 1/0	1.002 (0.458–2.189)	0.9967	0.862 (0.403–1.843)	0.7012
mSASSS at baseline	1.054 (1.034–1.074)	< 0.0001	1.039 (1.021–1.058)	< 0.0001
Smoking status, yes/no = 1/0	0.598 (0.346–1.031)	0.0644	0.573 (0.340–0.966)	0.0365
CRP at Week 24, n = 292
Age, yrs	1.027 (1.000–1.056)	0.0503	1.031 (1.004–1.059)	0.0224
CRP at Week 24	0.951 (0.749–1.208)	0.6818	0.976 (0.776–1.229)	0.8387
Disease duration, yrs	0.984 (0.949–1.021)	0.3934	0.992 (0.959–1.027)	0.6657
Male/female = 1/0	0.495 (0.262–0.936)	0.0304	0.543 (0.299–0.986)	0.0448
HLA-B27, positive/negative = 1/0	0.912 (0.416–2.003)	0.8193	1.020 (0.483–2.156)	0.9584
mSASSS at baseline	1.051 (1.031–1.070)	< 0.0001	1.037 (1.019–1.054)	< 0.0001
Smoking status, yes/no = 1/0	0.673 (0.392–1.158)	0.1525	0.605 (0.361–1.014)	0.0566
CRP change at Week 14, n = 291
Age, yrs	1.030 (1.002–1.059)	0.0375	1.033 (1.006–1.061)	0.0171
CRP change at Week 14	0.836 (0.719–0.971)	0.0190	0.839 (0.724–0.972)	0.0190
Disease duration, yrs	0.993 (0.957–1.031)	0.7160	0.999 (0.964–1.035)	0.9478
Male/female = 1/0	0.557 (0.294–1.054)	0.0720	0.570 (0.311–1.044)	0.0687
HLA-B27, positive/negative = 1/0	1.002 (0.454–2.211)	0.9968	0.883 (0.410–1.902)	0.7513
mSASSS at baseline	1.051 (1.031–1.071)	< 0.0001	1.037 (1.019–1.056)	< 0.0001
Smoking status, yes/no = 1/0	0.599 (0.345–1.040)	0.0688	0.579 (0.342–0.980)	0.0419
CRP change at Week 24, n= 292
Age, yrs	1.032 (1.004–1.061)	0.0239	1.036 (1.009–1.065)	0.0092
CRP change at Week 24	0.843 (0.733–0.969)	0.0162	0.828 (0.721–0.950)	0.0073
Disease duration, yrs	0.991 (0.955–1.028)	0.6220	1.000 (0.965–1.035)	0.9879
Male/female = 1/0	0.497 (0.261–0.946)	0.0331	0.543 (0.296–0.996)	0.0486
HLA-B27, positive/negative = 1/0	0.910 (0.411–2.013)	0.8156	1.039 (0.487–2.214)	0.9218
mSASSS at baseline	1.046 (1.027–1.066)	< 0.0001	1.032 (1.014–1.050)	0.0003
Smoking status, yes/no = 1/0	0.658 (0.381–1.137)	0.1339	0.585 (0.347–0.987)	0.0446

Variables	Radiographic Progression^**
	Week 104		Week 208
	OR (95% CI)	p	OR (95% CI)	p
CRP at baseline, n = 262
Age, yrs	1.014 (0.985–1.043)	0.3636	1.011 (0.983–1.040)	0.4430
CRP at baseline	1.094 (0.955–1.253)	0.1942	1.059 (0.926–1.212)	0.3998
Disease duration, yrs	0.983 (0.944–1.023)	0.4029	0.997 (0.960–1.036)	0.8827
Male/female = 1/0	0.509 (0.241–1.076)	0.0771	0.601 (0.291–1.242)	0.1693
HLA-B27, positive/negative = 1/0	0.814 (0.337–1.963)	0.6460	1.252 (0.542–2.893)	0.5986
mSASSS at baseline	1.037 (1.019–1.054)	< 0.0001	1.030 (1.012–1.047)	0.0008
Smoking status, yes/no = 1/0	0.974 (0.539–1.759)	0.9302	0.893 (0.506–1.577)	0.6965
CRP at Week 14, n = 265
Age, yrs	1.010 (0.982–1.039)	0.4960	1.008 (0.981–1.037)	0.5524
CRP at Week 14	0.976 (0.759–1.254)	0.8489	1.003 (0.793–1.269)	0.9809
Disease duration, yrs	0.983 (0.945–1.023)	0.4070	0.992 (0.955–1.031)	0.6918
Male/female = 1/0	0.531 (0.255–1.102)	0.0893	0.665 (0.326–1.357)	0.2626
HLA-B27, positive/negative = 1/0	0.838 (0.349–2.014)	0.6929	1.283 (0.556–2.961)	0.5589
mSASSS at baseline	1.041 (1.023–1.059)	< 0.0001	1.033 (1.016–1.051)	0.0001
Smoking status, yes/no = 1/0	0.977 (0.544–1.755)	0.9379	0.823 (0.467–1.451)	0.5011
CRP at Week 24, n = 265
Age, yrs	1.011 (0.983–1.040)	0.4364	1.009 (0.982–1.038)	0.5095
CRP at Week 24	1.024 (0.805–1.303)	0.8468	0.886 (0.682–1.153)	0.3678
Disease duration, yrs	0.979 (0.941–1.018)	0.2846	0.997 (0.961–1.035)	0.8743
Male/female = 1/0	0.559 (0.270–1.158)	0.1176	0.627 (0.307–1.281)	0.2003
HLA-B27, positive/negative = 1/0	0.828 (0.345–1.985)	0.6722	1.258 (0.547–2.896)	0.5892
mSASSS at baseline	1.038 (1.021–1.056)	< 0.0001	1.034 (1.017–1.051)	0.0001
Smoking status, yes/no = 1/0	1.006 (0.561–1.803)	0.9852	0.840 (0.478–1.479)	0.5464
CRP change at Week 14, n = 265
Age, yrs	1.013 (0.984–1.042)	0.3860	1.011 (0.983–1.039)	0.4563
CRP change at Week 14	0.862 (0.745–0.997)	0.0451	0.898 (0.778–1.037)	0.1425
Disease duration, yrs	0.990 (0.951–1.031)	0.6187	0.996 (0.959–1.035)	0.8564
Male/female = 1/0	0.530 (0.253–1.110)	0.0923	0.656 (0.320–1.345)	0.2499
HLA-B27, positive/negative = 1/0	0.825 (0.340–1.999)	0.6695	1.251 (0.540–2.898)	0.6016
mSASSS at baseline	1.038 (1.020–1.056)	< 0.0001	1.031 (1.014–1.049)	0.0003
Smoking status, yes/no = 1/0	0.970 (0.537–1.752)	0.9185	0.829 (0.469–1.466)	0.5191
CRP change at Week 24, n = 265
Age, yrs	1.014 (0.985–1.044)	0.3401	1.014 (0.986–1.042)	0.3452
CRP change at Week 24	0.898 (0.780–1.034)	0.1338	0.865 (0.753–0.993)	0.0394
Disease duration, yrs	0.984 (0.946–1.025)	0.4426	1.003 (0.966–1.042)	0.8811
Male/female = 1/0	0.560 (0.269–1.167)	0.1217	0.616 (0.299–1.267)	0.1882
HLA-B27, positive/negative = 1/0	0.847 (0.353–2.032)	0.7104	1.202 (0.522–2.769)	0.6661
mSASSS at baseline	1.036 (1.019–1.053)	< 0.0001	1.030 (1.013–1.047)	0.0006
Smoking status, yes/no = 1/0	0.980 (0.545–1.762)	0.9467	0.846 (0.479–1.495)	0.5653

↵* Syndesmophyte formation was defined as having ≥ 1 vertebral level on radiograph that changed from a score < 2 at baseline to an mSASSS of 2 or 3 at Week 104 or 208 according to at least 1 reader.
↵** Radiographic progression was defined as a change of ≥ 2 units in mSASSS from baseline to Week 104 or 208. Significant data are in bold face. CRP: C-reactive protein; mSASSS: modified Stoke Ankylosing Spondylitis Spine Score.