Table 2. Multivariable analysis of odds of Oxygen Therapy and Sustained oxygen therapy use among COPD patients.

	Odds of Any Oxygen Therapy (95% CI)	Odds of Sustained oxygen therapy (95% CI)
Age
66–74	Ref	Ref
75–84	1.03 (1.01–1.06)	1.01 (0.99–1.04)
≥85	0.99 (0.96–1.03)	0.91 (0.87–0.94)
Gender
Female	Ref	Ref
Male	0.87 (0.85–0.89)	0.83 (0.81–0.85)
Race
White	Ref	Ref
Black	0.73 (0.69–0.77)	0.77 (0.73–0.82)
Other	0.58 (0.54–0.62)	0.62 (0.57–0.67)
Low Socioeconomic Status
No	Ref	Ref
Yes	1.25 (1.21–1.29)	1.28 (1.24–1.32)
Elixhauser Comorbidity
0	Ref	Ref
1	1.04 (1.02–1.07)	1.12 (1.09–1.16)
≥2	1.55 (1.52–1.59)	1.59 (1.55–1.64)
Year
2001	Ref	Ref
2002	1.08 (1.05–1.11)	1.05 (1.02–1.09)
2003	1.14 (1.11–1.18)	1.13 (1.09–1.17)
2004	1.17 (1.14–1.21)	1.24 (1.20–1.28)
2005	1.21 (1.18–1.25)	1.21 (1.17–1.26)
2006	1.29 (1.25–1.33)	1.36 (1.31–1.41)
2007	1.32 (1.28–1.37)	1.43 (1.37–1.48)
2008	1.33 (1.29–1.38)	1.43 (1.37–1.48)
2009	1.29 (1.25–1.34)	0.78 (0.75–0.82)
2010	1.22 (1.18–1.26)	0.85 (0.82–0.88)
Region
New England	Ref	Ref
East North Central	1.64 (1.55–1.74)	1.54 (1.44–1.65)
East South Central	1.64 (1.54–1.75)	1.53 (1.42–1.65)
Middle Atlantic	0.98 (0.92–1.05)	1.01 (0.94–1.09)
Mountain	2.86 (2.66–3.07)	2.54 (2.35–2.75)
Pacific	1.39 (1.30–1.48)	1.30 (1.21–1.41)
South Atlantic	1.63 (1.54–1.72)	1.54 (1.45–1.65)
West North Central	1.94 (1.81–2.08)	1.83 (1.69–1.98)
West South Central	1.70 (1.60–1.81)	1.55 (1.44–1.66)