Table 3.

Relative Risk of Experiencing Time to Event Outcomes by COPD Treatment Classification

Outcome by Exposure	2017 Groups A and B		2017 Groups C and D
	Crude Hazard Ratio (95% CI)	Adjusted Hazard Ratioa (95% CI)	Crude Hazard Ratio (95% CI)	Adjusted Hazard Ratioa (95% CI)
Primary outcome
Death/first hospitalization for COPDb
Aligned	Referent	Referent	Referent	Referent
Undertreated	0.78 (0.46-1.34)	0.92 (0.61-1.40)	0.96 (0.66-1.40)	0.93 (0.57-1.52)
Overtreated	1.09 (0.71-1.67)	1.02 (0.67-1.54)	0.47 (0.20-1.09)	0.55 (0.24-1.28)
Secondary outcomes
Deathb
Aligned	Referent	Referent	Referent	Referent
Undertreated	0.73 (0.31-1.76)	0.86 (0.39-1.88)	2.09 (0.94-4.64)	1.76 (0.74-4.19)
Overtreated	0.93 (0.54-1.60)	0.96 (0.63-1.47)	0.32 (0.12-0.90)	0.52 (0.08-3.46)
First hospitalization for COPDc
Aligned	Referent	Referent	Referent	Referent
Undertreated	0.83 (0.43-1.64)	0.94 (0.57-1.54)	0.72 (0.45-1.18)	0.83 (0.41-1.71)
Overtreated	1.22 (0.76-1.97)	1.08 (0.68-1.71)	0.42 (0.14-1.27)	0.46 (0.17-1.24)
First COPD exacerbationd
Aligned	Referent	Referent	Referent	Referent
Undertreated	0.91 (0.53-2.15)	0.96 (0.61-1.49)	0.93 (0.65-1.34)	1.00 (0.55-1.81)
Overtreated	1.60 (1.19-2.15)	1.42 (1.09-1.87)	1.24 (0.80-1.93)	1.05 (0.53-2.04)

^aCox proportional hazard models adjusted for baseline age, sex, Charlson comorbidity index score, smoking status, and number of all-cause hospitalizations in year before randomization, stratified by baseline Global Initiative for Chronic Obstructive Lung Disease stage and BODE index.

^bIncludes all 738 patients enrolled in the Long-term Oxygen Treatment Trial.

^cExcludes patients who died prior to experiencing an initial COPD-related hospitalization (n = 43).

^dExcludes patients who died prior to experiencing an initial COPD exacerbation (n = 39).