A. Univariable analyses for clinical baseline factors and early-stage infliximab (IFX) trough levels (ITL) for ITL absence at week (W) 54.

Factors	OR	95%CI
At baseline
Female sex	1.59	0.29-8.69
Age	1.04	1.03-1.07
Rheumatoid factor	0.54	0.13-2.18
ACPA	0.21	0.24-1.81
Body mass index	1.05	0.93-1.18
DAS28	0.70	0.46-1.05
MTX non-use	4.20	1.33-13.32
CRP levels	0.98	0.95-1.05
Levels below cut-off at W2 (21.2 μg/mL)	12.40	3.48-44.15
Levels below cut-off at W6 (4.4 μg/mL)	44.33	7.99-246.03