Table 4.

Cox regression time-to-event analysis showing associations of methotrexate exposure and baseline covariates with time from RA first symptoms to RA-ILD onset

	Primary analysis, RA-ILD onset after any csDMARD exposure (n=67)		Extended cohort, including RA-ILD onset pre any csDMARD (n=92)	P value
	HR (95% CI)	P value	HR (95% CI)
Methotrexate exposure	0.54 (0.28 to 1.06)	0.072	0.41 (0.23 to 0.75)	0.004
Age RA onset	1.03 (1 to 1.06)	0.048	1.03 (1 to 1.06)	0.028
Smoking, ever, baseline	1.09 (0.52 to 2.26)	0.817	1.16 (0.61 to 2.22)	0.654
Male gender	1.02 (0.51 to 2.03)	0.966	0.85 (0.47 to 1.54)	0.587
RF positive, baseline	0.96 (0.69 to 1.32)	0.799	1.08 (0.85 to 1.38)	0.512
Onset – OPD	0.98 (0.94 to 1.03)	0.424	0.98 (0.94 to 1.02)	0.276
Baseline major comorbidities*	1.26 (0.69 to 2.28)	0.452	1.09 (0.63 to 1.9)	0.762

Onset – OPD: time from first RA symptoms to first hospital outpatient appointment.

*Excluding respiratory.

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