Estimating the U.S. prevalence of chronic obstructive pulmonary disease using pre- and post-bronchodilator spirometry: the National Health and Nutrition Examination Survey (NHANES) 2007–2010

Table 1 Distribution of persons eligible for spirometry and examined

	Pre-bronchodilator spirometry				Post-bronchodilator spirometry
	Eligible^apersons		Examined^bpersons		Eligible^cpersons		Examined^dpersons
	n	Percent (unweighted)	Percent of eligible persons (unweighted)	Chi-square^ep-value	n	Percent (unweighted)	Percent of eligible persons (unweighted)	Chi-square^ep-value
Total	7,104	100.0	77.1		1,110	100.0	50.8
Gender				0.086				0.001
Male	3,495	49.2	78.0		675	60.8	54.7
Female	3,609	50.8	76.3		435	39.2	44.8
Race and ethnic origin				<.001				0.092
Non-Hispanic white	3,362	47.3	80.4		705	63.5	53.2
Non-Hispanic black	1,437	20.2	72.8		195	17.6	42.1
Mexican American	1,217	17.1	75.9		99	8.9	52.5
Age				<.001				<.001
40–59	3,839	54.0	81.4		455	41.0	58.2
60–79	3,265	46.0	72.0		655	59.0	45.6
Education				<.001				<.001
Less than 12th grade	2,270	32.0	69.2		331	29.9	44.4
HS Grad/GED/Equivalent	1,655	23.3	78.1		301	27.2	46.8
Some College or AA degree	1,773	25.0	80.9		272	24.6	56.6
College Graduate or above	1,395	19.7	84.1		204	18.4	59.8
Smoking status				0.373				0.022
Current smoker	1,479	20.8	75.5		378	34.1	45.2
Past smoker	2,110	29.7	77.9		414	37.3	50.7
Never smoked	3,512	49.4	77.3		317	28.6	57.7
Previous Diagnosis of COPD^f				<.001				<.001
No	6,680	94.0	78.5		994	89.6	53.2
Yes	424	6.0	55.2		116	10.5	30.2

^aNumber of persons aged 40–79 years who attended the NHANES MEC exam, 2007-10.
^bPercent of those eligible with a complete pre-bronchodilator spirometry examination and acceptable quality exam results by ATS/ERS Criteria or had a minimum of 2 curves where FEV1 values were within 200 ml and FVC values were within 200 ml. This combination is denoted in the data as SPXNSTAT=1.
^cSubset of those persons with a complete, acceptable quality pre-bronchodilator spirometry examination that have results suggestive of airflow obstruction (pre-bronchodilator FEV1/FVC < .7 or < LLN)
^dPercent of those eligible with a complete post-bronchodilator spirometry examination and acceptable quality exam results (minimum 2 curves where FEV1 values were within 200 ml and FVC values were within 200 ml). This combination is denoted in the data as SPXBSTAT=1.
^eChi-square values computed for differences between examined and non-examined (eligible less examined) persons.
^fSelf-reported, health care provider diagnosed COPD assessed by an affirmative response to either ever having emphysema or still having chronic bronchitis.

ISSN: 1465-993X