Assessing health-related quality of life in COPD: comparing generic and disease-specific instruments with focus on comorbidities

Table 2 Results of regression analyses

		EQ-5D utility		EQ-5D VAS		CAT score		SGRQ total score
		Estimate	p-value	Estimate	p-value	Estimate	p-value	Estimate	p-value
COPD	Grade 4	-0.13	<0.0001	-22.11	<0.0001	7.92	<0.0001	31.71	<0.0001
	Grade 3	-0.04	0.005	-14.61	<0.0001	4.98	<0.0001	20.41	<0.0001
	Grade 2	-0.006	0.69	-5.67	<0.0001	2.47	<0.0001	10.28	<0.0001
	Grade 1	ref.		ref.		ref.		ref.
Comorbidities	High number	-0.09	<0.0001	-5.75	<0.0001	2.91	<0.0001	7.90	<0.0001
	Low number	ref.		ref.		ref.		ref.
Age	>74 years	-0.01	0.59	-1.44	0.38	-2.05	0.001	1.20	0.45
	65 – 74 years	0.01	0.36	1.04	0.43	-1.55	0.002	0.23	0.86
	55 – 64 years	-0.001	0.97	0.26	0.84	-0.60	0.23	0.26	0.84
	<55 years	ref.		ref.		ref.		ref.
Sex	Female	-0.02	0.06	1.53	0.06	0.16	0.60	0.90	0.25
	Male	ref.		ref.		ref.		ref.
School education	Higher	0.05	<0.0001	3.08	0.003	-1.77	<0.0001	-4.58	<0.0001
School education	Secondary	0.02	0.06	3.10	0.001	-0.88	0.01	-3.26	0.0002
	Basic	ref.		ref.		ref.		ref.
Smoking status	Current smoker	-0.01	0.46	-0.13	0.94	0.74	0.25	1.19	0.47
Smoking status	Former smoker	-0.02	0.29	0.29	0.85	0.18	0.77	1.45	0.34
	Never smoker	ref.		ref.		ref.		ref.
BMI	Overweight	-0.03	0.007	-1.53	0.09	0.14	0.68	1.50	0.08
	Obese	-0.06	<0.0001	-4.68	<0.0001	1.64	<0.0001	6.40	<0.0001
	Underweight	0.002	0.93	-5.59	0.01	0.87	0.28	1.97	0.34
	Normal weight	ref.		ref.		ref.		ref.

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