Table 1

SPIROMICS enrolment strata

Non-smokers (stratum 1)Smokers (stratum 2)Mild/moderate COPD (stratum 3)Severe COPD (stratum 4)
Smoking status<1 pack-year>20 pack-years>20 pack-years>20 pack-years
Bronchodilator status for assessing lung functionPre-bronchodilatorPost-bronchodilatorPost-bronchodilatorPost-bronchodilator
FEV1/FVC ratio criteriaFEV1/FVC>0.7FEV1/FVC>0.7FEV1/FVC<0.7FEV1/FVC<0.7
Other lung function criteriaFVC>LLNFVC>LLNFEV1>50% pred.FEV1<50% pred.
Sample sizeN=200 (6.25%)N=900 (28.1%)N=1500 (46.9%)N=600 (18.75%)
  • COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; LLN, lower limit of normal; SPIROMICS, Subpopulations and Intermediate Outcomes in COPD Study.