Design of a multi-center immunophenotyping analysis of peripheral blood, sputum and bronchoalveolar lavage fluid in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)

Table 1 Planned subject enrollment distribution by strata

	Never-smokers	Smokers without airflow obstruction	Smokers with mild to moderate COPD	Smokers with severe COPD
Smoking status	<1 pack year	>20 pack years	>20 pack years	>20 pack years
Lung function	FEV₁/FVC >0.7	FEV₁/FVC >0.7	FEV₁ > 50% predicted	50% > FEV₁ > 30% predicted
Sample size	N = 60 (20%)	N = 60 (20%)	N = 140 (47%)	N = 40 (13%)

ISSN: 1479-5876