Table 3.

Logistic Regression on Factors Associated with Bilateral THA in AS Patients with Advanced Hip Involvement

Parameter	OR (95% CI)	P value
Male	1.013 (0.402 to 2.549)	0.979
Age at onset	1.021(0.984 to 1.059)	0.272
Disease duration	1.009(0.974 to 1.045)	0.631
Bilateral onset in hips	10.177(5.713 to 18.130)	<0.001
Administration of TNF inhibitors	0.346(0.142 to 0.838)	0.019
Flexion contracture	1.447(0.802 to 2.612)	0.220
BASRI-hip score of 4	4.133(2.308 to 7.400)	<0.001
ESR	1.018(1.001 to 1.035)	0.043
CRP	0.920(0.788 to 1.073)	0.287

Abbreviations: THA, total hip arthroplasty; AS, ankylosing spondylitis; OR, odds ratio; CI, confidence interval; TNF, tumour necrosis factor; BASRI, the Bath Ankylosing Spondylitis Radiology Hip Index; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein.