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 function | Pre-bronchodilator | Post-bronchodilator | Post-bronchodilator | Post-bronchodilator |
| FEV1/FVC ratio criteria | FEV1/FVC>0.7 | FEV1/FVC>0.7 | FEV1/FVC<0.7 | FEV1/FVC<0.7 |
| Other lung function criteria | FVC>LLN | FVC>LLN | FEV1>50% pred. | FEV1<50% pred. |
| Sample size | N=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.