Table 3.

Prognostic factors for survival

Variable	N	Univariable Cox hazard analysis			Multivariable Cox hazard analysis
		HR	95% CI	P value	HR	95% CI	P value
Age		1.05	1.03 to 1.07	<0.001	1.06	1.03 to 1.08	<0.001
Male	128	Ref			Ref
Female	205	0.62	0.43 to 0.90	0.012	0.75	0.51 to 1.11	0.158
Concomitant ILD	122	1.60	1.11 to 2.32	0.012	1.65	1.12 to 2.42	0.012
RA and PMR	52	0.97	0.56 to 1.67	0.901	0.98	0.44 to 2.20	0.967
Primary vasculitis syndrome	116	1.63	1.12 to 2.36	0.010	1.14	0.57 to 2.26	0.711
Systemic lupus erythematosus	49	0.87	0.51 to 1.46	0.589	2.07	0.94 to 4.58	0.071
Inflammatory myositis	60	0.69	0.40 to 1.18	0.177	1.15	0.52 to 2.54	0.722
Systemic sclerosis	13	0.71	0.22 to 2.23	0.552	0.81	0.22 to 2.96	0.746
Others	43	0.82	0.21 to 3.23	0.775
Oxygen administration on admission	76	0.84	0.52 to 1.35	0.465

Univariable and multivariable Cox proportional hazards regression analyses were performed.

ILD, interstitial lung disease; PMR, polymyalgia rheumatica; RA, rheumatoid arthritis; Ref, reference.