Table 4.

Associations between PF and covariates in simple and multivariable analyses

Variables	Simple variable analysis		Multivariable analysis
	OR (95% CI)	P-value	OR (95% CI)	P-value
Sex	0.64 (0.35, 1.24)	0.17	0.86 (0.44, 1.74)	0.67
Age at RA onset	1.10 (1.03, 1.09)	2.9e-05	1.10 (1.03, 1.09)	0.0001
Smoking +/−a	1.80 (0.92, 3.60)	0.099	1.50 (0.77, 3.21)	0.25
ACPA +/−	1.40 (0.70, 3.01)	0.37	1.20 (0.52, 2.81)	0.73
RF +/−	2.70 (1.10, 7.80)	0.042	3.0 (1.10, 9.58)	0.045
HLA-shared epitope +/−b	0.97 (0.51, 2.00)	0.94	0.88 (0.44, 1.89)	0.74
MTX started at index date	0.27 (0.14, 0.51)	4.3e-05	0.30 (0.16, 0.60)	0.00048
BMIc	1.0 (0.95, 1.08)	0.64	1.00 (0.95, 1.10)	0.54
DAS28 at index date	0.99 (0.80, 1.22)	0.92	0.91 (0.72, 1.14)	0.39

^aSmoking refers to ever being a smoker.

^bHLA-shared epitope includes 0401/0404/0405/0408/0101.

^cMissing values were imputed.