Table 2.

Associations of titrated oxygen requirement with survival time

	Titrated oxygen requirement (L/min)					Hazard ratio per 1 L/min increase in titrated oxygen requirement
	0	1 to 2	3 to 6	8 to 15*	p for trend	Hazard ratio (95% CI)	P value
Derivation cohort (n = 104)
Unadjusted hazard ratio (95% CI)	Ref	3.7 (1.1 – 13)	5.3 (1.6 – 18)	7.5 (2.1 – 27)	0.003	1.14 (1.06 – 1.24)	<0.001
Adjusted hazard ratio (95% CI)
Model 1	Ref	1.8 (0.5 – 6.9)	3.1 (0.8 – 11)	6.7 (1.7 – 26)	0.004	1.16 (1.06 – 1.27)	0.001
Model 2	Ref	1.9 (0.5 – 7.3)	3.0 (0.8 – 11)	6.7 (1.7 – 25)	0.005	1.16 (1.06 – 1.27)	0.001
Validation cohort (n = 151)
Unadjusted hazard ratio (95% CI)	Ref	2.2 (0.7 – 7.2)	1.2 (0.4 – 3.3)	7.7 (2.7 – 22)	<0.001	1.13 (1.06 – 1.20)	<0.001
Adjusted hazard ratio (95% CI)
Model 1	Ref	1.4 (0.4 – 5.4)	0.7 (0.2 – 2.4)	3.8 (1.01 – 15)	0.01	1.10 (1.01 – 1.19)	0.02
Model 2	Ref	1.4 (0.4 – 5.3)	0.7 (0.2 – 2.3)	3.9 (1.05 – 15)	0.01	1.10 (1.01 – 1.18)	0.02

Abbreviations: CI = confidence interval

^*Two participants in the validation cohort who were titrated to 25 L/min via non-rebreather mask are included in this group.

Model 1: Adjusted for age, six-minute walk distance, and oxygen saturation at end six-minute walk test.

Model 2: Model 1 + adjustment for forced vital capacity % predicted