Table 3.

Multiple adjusted Cox proportional hazard model for analysis of drug discontinuation of a first TNF inhibitor in HLA-B27 negative vs. positive patients with complete availability of data on covariates

Complete case analysis	Model 1			Model 2
Variable	HR	95% CI	P	HR	95% CI	P
HLA-B27 negative (Ref: HLA-B27 positive)	1.58	1.30; 1.91	<0.001	1.10	0.78; 1.55	0.58
Female sex (Ref: male sex)	1.50	1.26; 1.78	<0.001	1.65	1.20; 2.26	0.002
Family history SpA positive	1.00	0.84; 1.20	0.97	1.09	0.81; 1.46	0.56
Elevated CRP				0.71	0.53; 0.95	0.02
BASDAI				1.00	0.93; 1.08	0.91
Enthesitis				0.77	0.56; 1.07	0.12
Education vocational (Ref: compulsory)				0.80	0.51; 1.26	0.34
Education academic (Ref: compulsory)				0.91	0.56; 1.49	0.72
BMI 25-30 (Ref: BMI <25)				1.15	0.83; 1.60	0.40
BMI >30 (Ref: BMI ≤25)				1.40	0.90; 2.19	0.13
Age				1.00	0.98; 1.01	0.74
Uveitis ever				0.91	0.65; 1.29	0.60
Good response to NSAIDs				1.17	0.80; 1.70	0.41
nr-axSpA (Ref: r-axSpA)				1.09	0.78; 1.53	0.61
Current smoking				1.08	0.80; 1.46	0.62

Analysis performed in 902 patients (545 events) in model 1 and 337 patients (208 events) in model 2. Statistically significant results are shown in bold. BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASMI, Bath Ankylosing Spondylitis Mobility Index; BMI, body mass index; CRP, C-reactive protein; HLA-B27, human leucocyte antigen-B27; nr-axSpA, nonradiographic axial spondyloarthritis; NSAIDs, non-steroidal anti-rheumatic drugs; r-axSpA, radiographic axial spondyloarthritis; Ref, reference; TNF, tumor necrosis factor