Table 3.

OR for mortality

	OR	95% CI	χ2	P value
Age	1.08	1.02 to 1.15	7.22	0.007*
Clinical frailty score
CFS 1–4	Ref			0.617
CFS 5–9	1.56	0.27 to 11.09	0.25
Oxygen therapy prior to respiratory support
Moderate	Ref			0.088
High	4.18	0.81 to 29.70	2.91
Full proning
Unsuccessful	Ref			0.031*
Successful	0.06	0.00 to 0.80	4.68
CPAP
Required transfer onto HFNO	Ref			0.761
Required CPAP only	0.76	0.13 to 4.88	0.09

Multivariate logistic regression (Firth bias reduced).

*p<0.05

CFS, clinical frailty score; CPAP, continuous positive airway pressure; HFNO, high flow nasal oxygen.