Table 4.

Potential prognostic factors for all-cause mortality (clinical outcome analysis population).

Factor		No. of Patients	HR	95% CI
Demographics
Sex	Male^{^a}	52	—	—
	Female	117	0.71	0.26-1.94
Age, yrs	< 15	0	NA	NA
	15 to < 30	3	NA	NA
	30 to < 40	6	NA	NA
	40 to < 50	31	0.82	0.22-3.09
	50 to < 60	63	0.62	0.20-1.91
	≥ 65^{^a}	66	—	—
Weight, kg	< 30	0	NA	NA
	30 to < 50^{^a}	63	—	—
	50 to < 70	80	0.86	0.29-2.56
	≥ 70	21	1.48	0.37-5.92
Inpatient/outpatient	Inpatient	143	2.89	0.38-21.89
	Outpatient^{^a}	26	—	—
Smoking	No^{^a}	130	—	—
	Yes	38	1.66	0.58-4.78
Dysphagia	Absence^{^a}	159	—	—
	Presence	10	NA	NA
Underlying disease
Idiopathic inflammatory myopathies	PM^{^a}	46	—	—
	CADM	61	9.04	1.18-69.51
	Classic DM	62	2.09	0.22-20.05
Disease duration, yrs	< 1^{^a}	121	—	—
	1 to < 5	25	NA	NA
	≥ 5	11	0.78	0.10-5.99
Symptoms other than muscle, lung, and skin	Absence^{^a}	64	—	—
Symptoms other than muscle, lung, and skin	Presence	105	1.35	0.47–3.89
Raynaud phenomenon	Absence^{^a}	149	—	—
	Presence	20	0.99	0.22–4.34
Arthritis or joint pain	Absence^{^a}	100	—	—
	Presence	69	1.12	0.42–3.01
Cardiopathy	Absence^{^a}	161	—	—
	Presence	8	3.01	0.68–13.28
Fever	Absence^{^a}	134	—	—
	Presence	35	2.55	0.93–7.03
IP
IP duration	< 1 month^{^a}	26	—	—
	1 to < 3 months	40	0.42	0.12–1.48
	3 to < 6 months	25	NA	NA
	6 to < 12 months	20	0.39	0.08–1.92
	1 to < 3 yrs	15	NA	NA
	≥ 3 yrs	19	0.43	0.09–2.13
Primary/relapse	Primary^{^a}	134	—	—
	Relapse	35	0.86	0.24–3.00
Radiographically speculated histological type	NSIP^{^a}	130	—	—
Radiographically speculated histological type	UIP	11	NA	NA
	OP	17	0.51	0.07–3.88
	DAD	5	4.58	1.03–20.38
SaO₂, %	< 85	1	NA	NA
	85 to < 90	2	NA	NA
	90 to < 95	22	7.53	2.73–20.82
	≥ 95^{^a}	120	—	—
Oxygen administration	Absence^{^a}	151	—	—
	Presence	18	3.82	1.23–11.88
Ferritin, ng/mL	< 500^{^a}	92	—	—
	500 to < 1500	21	8.61	2.51–29.45
	1500 to < 2500	3	NA	NA
	2500 to < 3500	2	NA	NA
	≥ 3500	0	NA	NA
Anti-Jo-1 antibody	Positive	27	0.26	0.03–2.01
	Negative^{^a}	112	—	—
Anti-ARS antibody	Positive	74	0.12	0.03–0.53
	Negative^{^a}	58	—	—
Anti-MDA5 antibody	Positive	28	8.16	1.03–64.47
	Negative^{^a}	21	—	—
KL-6, U/mL	< 1000^{^a}	83	—	—
	≥ 1000	71	0.62	0.21–1.84
SP-D, ng/mL	< 100^{^a}	30	—	—
	≥ 100	50	0.59	0.17–2.05
Mode of onset	Subacute^{^a}	73	—	—
	Acute exacerbation	22	1.00	0.28–3.65
	Chronic	46	0.48	0.13–1.74
	Asymptomatic	28	NA	NA

↵^aReference. For categories with no events (death), HR and 95% CI are shown as NA. Anti-ARS: antiaminoacyl tRNA synthetase; anti-MDA5: antimelanoma differentiation-associated gene 5; CADM: clinically amyopathic dermatomyositis; DAD: diffuse alveolar damage; DM: dermatomyositis; HR: hazard ratio; IP: interstitial pneumonia; KL-6: Krebs von den Lungen 6; NA: not available; NSIP: nonspecific interstitial pneumonia; OP: organizing pneumonia; PM: polymyositis; SaO₂: arterial oxygen saturation; SP-D: surfactant protein D; UIP: usual interstitial pneumonia.