Table 1.

Characteristics of the included studies

Study/year	Design	Country	Setting	Underlying conditions	Patient characteristics (NIV/Ctrl)					Primary outcome	Mortality follow up
					Patient number	Age, years	Disease severity	RR/min	PO2:FiO2
Antonelli et al. 2000 [10]	P, RC, SC	Italy	ICU	Organ transplant	20/20	45/44	SAPS I 13 ± 4/13 ± 3	38 ± 3/37 ± 1	129/129	Need of intubation	28 days
Hilbert et al. 2001 [11]	P, RC, SC	France	ICU	Mixed immunocompromised	26/26	48/50	SAPS II 45 ± 10/42 ± 9	35 ± 3/36 ± 3	141/136	Need of intubation	28 days
Squadrone et al. 2010 [12]	P, RC, SC	Italy	Hematology ward	Hematologic malignancy	20/20	50/49	SAPS II 41.3 ± 6/42 ± 7	30/29	282/256	Need of intubation	90 days
Wermke et al. 2012 [13]	P, RC, SC	Germany	Hematology ward	Allogeneic HSCT	42/44	53/52	NR	NR	250–300	Mortality	5 years
Lemiale et al. 2015 [14]	P, RC, MC	France/Belgium	ICU	Mixed immunocompromised	191/183	64/61	SOFA 5 (3–7)/5 (3–7)	25 (21–30)/27 (21–31)	130/156	Mortality	180 days

HFNC heated and humidified high flow oxygen delivered by nasal cannula, HSCT hematopoietic stem cell transplantation, ICU intensive care unit, MC multi-center, NIV non-invasive ventilation, NR not reported, P prospective, RC randomized controlled, RR respiratory rate, SAPS simplified acute physiologic score, SC single-center, SOFA sequential organ failure assessment score