High-flow nasal oxygen vs. conventional oxygen therapy in patients with COVID-19 related acute hypoxemic respiratory failure and a do not intubate order: a multicentre cohort study

Table 2 Odds ratio’s for in-hospital mortality at time points COT ≥ 6 L/min or at maximum level

Prior to (potential) HFNO initiation	COT at ≥6 L/min		COT at maximal level
	OR [95% CI]	p-value	OR [95% CI]	p-value
HFNO vs. COT	0.72 (0.34–1.54)	0.40	0.85 (0.40–1.78)	0.66
Confounders
Age (per 1-year increase)	1.03 (0.99–1.07)	0.20	1.03 (0.99–1.07)	0.21
Clinical frailty scale*
Vulnerable vs. Fit	2.06 (0.93–4.56)	0.08	2.46 (1.06–5.72)	0.04
Frail vs. Fit	1.20 (0.54–2.68)	0.66	1.57 (0.67–3.71)	0.30
Dexamethasone (yes/no)	0.58 (0.21–1.60)	0.29	0.69 (0.24–1.99)	0.50
SpO₂ (per 1%-point increase)	0.90 (0.83–0.98)	0.02	0.90 (0.82–0.98)	0.02
FiO₂ ^‡
Category 3 vs. 2	0.81 (0.33–2.01)	0.65	1.35 (0.47–3.85)	0.57
Category 4 vs. 2	1.43 (0.68–3.03)	0.35	4.75 (1.86–12.13)	<0.01
RR (per 1-breath/min increase)	1.01 (0.96–1.05)	0.76	1.02 (0.97–1.07)	0.43

Multivariable logistic regression analysis for outcome in-hospital mortality
*Clinical Frailty Scale was divided in category 1) fit 1–3, category 2) vulnerable 4–5, category 3) frail 6–9. ^‡FiO₂: estimated fraction of inspired oxygen, divided into three categories: group 1) room air, group 2) nasal oxygen 1–6 L/min or air-entrainment mask 10 L/min, group 3) air-entrainment mask 15 L/min or non-rebreathing mask 10 L/min and group 4) non-rebreathing mask 15 L/min
CI confidence interval, COT conventional oxygen therapy, HFNO high-flow nasal oxygen, OR odds ratio, RR respiratory rate, SpO₂ oxygen saturation

ISSN: 1465-993X