Table 3.

Factors associated with IFNα positivity at day 1 and week 24

	OR for IFNα positivity at day 1a	95% CI	OR for IFNα positivity at week 24a	95% CI
RF+ACPA+b	8.92	4.21–22.04	5.24	2.02–17.95
Current smokerb	1.70	0.91–3.15	2.18	1.01–4.56
CDAI day 1c	1.02	1.00–1.04	1.03	1.00–1.06
CRP day 1d	1.00	0.99–1.01	1.00	0.98–1.01

Multivariable logistic regression with IFNα positivity at day 1 and week 24 as the dependent variable. At day 1, IFNα-positive (n = 91) and IFNα-negative (n = 255). At week 24, IFNα-positive (n = 41) and IFNα-negative (n = 305)

RF rheumatoid factor, ACPA anti-citrullinated protein antibodies, CDAI clinical disease activity index

^aIFNα positivity defined as IFNα protein level above 136 fg/mL

^bYes versus no

^cPer point increase

^dPer 1 mg/L increase