Table 3.

Multivariate logistic analysis showing covariates independently associated with RA-ILD development

	Primary analysis, RA-ILD onset after any csDMARD exposure (n=67)	Wald test	Extended cohort, including RA-ILD onset prior to any csDMARD (n=92)	Wald test
	OR (95% CI)	P value	OR (95% CI)	P value
Methotrexate exposure	0.85 (0.49 to 1.49)	0.578	0.48 (0.3 to 0.79)	0.004
Age RA onset	1.04 (1.02 to 1.06)	<0.001	1.04 (1.02 to 1.06)	<0.001
Smoking, ever, baseline	2.21 (1.21 to 4.03)	0.01	1.91 (1.13 to 3.25)	0.016
Male gender	1.44 (0.83 to 2.48)	0.193	1.74 (1.05 to 2.86)	0.03
RF positive, baseline	2.02 (1.07 to 3.82)	0.029		n.s.
RA nodules, baseline		n.s.	2.19 (1.08 to 4.41)	0.029
Onset − OPD	1.04 (1.00 to 1.07)	0.027	1.03 (1.0 to 1.07)	0.04
Baseline major comorbidities*	0.62 (0.40 to 0.95)	0.027	0.67 (0.46 to 0.98)	0.037
Baseline ESR	-	n.s.	1.01 (1.0 to 1.02)	0.047

Onset − OPD: time from first RA symptoms to first hospital out patient appointment.

Note: variables not reported did not reach statistical significance in the respective models.

*Excluding respiratory.

csDMARD, conventional synthetic disease-modifying antirheumatic drugs; RA-ILD, rheumatoid arthritis interstitial lung disease; RF, rheumatoid factor.