B. Multivariable logistic regression analysis for IFX absence at W54 including ITL at W2 (Model I) and at W6 (Model II) as possible predictors.

Factors	OR	95%CI
Model I
Female sex	1.09	0.09-13.18
Age	1.09	1.03-1.17
DAS28	0.64	0.36-1.14
MTX non-use	12.26	1.83-82.22
Levels below cut-off at W2 (21.2 μg/mL)	15.85	2.95-85.03
Model II
Female sex	0.65	0.05-7.97
Age	1.05	0.98-1.12
DAS28	0.64	0.31-1.30
MTX non-use	6.91	1.04-45.84
Levels below cut-off at W6 (4.4 μg/mL)	86.64	6.58-1139.99

ACPA, anti-cyclic citrullinated peptide antibodies; CRP, C-reactive protein; CI, confidence interval; DAS28, Disease Activity Score in 28 joints; MTX, methotrexate; OR, odds ratio; TNF-α, tumour necrosis factor α; ITL, Infliximab trough levels.