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information on those SHHS spirometry variables. These were called
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methods underlying the source spirometry measurements could have differed
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airflow_limitation
under
Clinical Data/Diagnostic Studies/Lung Function
in
HCHS variables
This variable is based on the empirical evidence from the spirometry that the ratio of FEV1 to FVC is below the level defined by the ATS as indicative of restricted airflow. Defined only for valid spirometries.
airflow_obstruction
under
Clinical Data/Diagnostic Studies/Lung Function
in
HCHS variables
This variable is based on the empirical evidence from the spirometry that the ratio of FEV1 to FVC is below the level defined by the ATS as indicative of restricted airflow.
copd_by_bd_allpre
under
Clinical Data/Diagnostic Studies/Lung Function
in
HCHS variables
This variable is based on the post-bronchodilator measurement of the FEV1 to FVC ratio. The airflow remains restricted after the administration of albuterol. This variable is also defined for all participants who did not conduct a post-spirometry exam. Defined only for valid spirometries.
postbd_expected
under
Clinical Data/Diagnostic Studies/Lung Function
in
HCHS variables
This variable is a flag for whether a post bronchodilator was expected, based on the premeasurement. A post measurement was expected if the FEV1 to FVC ratio was less than 70% or less than the lower limit of normal for FEV1/FVC%.
postbd_prebd_diff
under
Clinical Data/Diagnostic Studies/Lung Function
in
HCHS variables
This variable is based on the ratio of the measured FEV1 difference from postbronchodilator and pre-bronchodilator exams over the Predicted FEV1 calculated prebronch (both values must be non-missing, and the post-bronchodilator spirometry examinations must be valid).
postbd_prebd_diff_gt12_v2
under
Clinical Data/Diagnostic Studies/Lung Function
in
HCHS variables
This variable is based on the ratio of the measured FEV1 difference from postbronchodilator and pre-bronchodilator exams over the Predicted FEV1 calculated prebronch (both values must be non-missing, and the post-bronchodilator spirometry examination must be valid) among participants with pre FEV1/FVC<70 only (ignores LLN comparison).