Table 1

Comparison of clinical characteristics in patients with COVID-19 with and without idiopathic pulmonary fibrosis (IPF) before and after propensity score matching

Variable	Before propensity matching						After propensity matching
	IPF cohort (n=251)		Non-IPF cohort (n=310 809)		Standard difference	P value	IPF cohort (n=251)		Non-IPF cohort (n=251)		Standard difference	P value
	Number	Per cent/ SD	Number	Per cent/ SD	Standard difference	P value	Number	Per cent/ SD	Number	Per cent/ SD	Standard difference	P value
Demographics
Age (mean, SD)	68.30	12.20	45.80	18.90	1.41	<0.01	68.30	12.20	690	12.90	0.06	0.52
Male	143	56.97	138 248	44.48	0.25	<0.01	143	56.97	142	56.57	0.01	0.93
Female	108	43.03	171 351	55.13	0.24	<0.01	108	43.03	109	43.43	0.01	0.93
Body mass index (30 and above)	99	39.44	50 100	16.12	0.54	<0.01	99	39.44	92	36.65	0.06	0.52
African American	37	14.74	57 982	18.66	0.11	0.11	37	14.74	37	14.74	<0.01	1
Caucasian	175	69.72	179 702	57.82	0.25	<0.01	175	69.72	185	73.71	0.09	0.32
Hispanic or Latino	38	15.14	48 701	15.67	0.01	0.82	38	15.14	20	7.97	0.01	0.23
Comorbidities
Hypertension	200	79.68	81 038	26.07	1.27	<0.01	200	79.68	201	80.08	0.01	0.91
Chronic kidney disease	99	39.44	17 761	5.71	0.88	<0.01	99	39.44	92	36.65	0.06	0.52
Chronic lower respiratory diseases	185	73.71	45 324	14.58	1.48	<0.01	185	73.71	185	73.71	<0.01	1
Diabetes mellitus	127	50.60	41 489	13.35	0.87	<0.01	127	50.60	126	50.20	0.01	0.93
Ischaemic heart disease	143	56.97	23 683	7.62	1.24	<0.01	143	56.97	152	60.56	0.07	0.41
Nicotine dependence	26	10.36	20 169	6.49	0.14	0.01	26	10.36	28	11.16	0.03	0.77