Recruitment of adequate numbers of subjects distributed between controls and four COPD GOLD stages is a key factor for success. Recruitment by age, gender, race, and disease status for each clinical study center is monitored on a real-time basis by the Data Coordinating Center (DCC). A Certificate of Confidentiality from the US Department of Health and Human Services was obtained at the onset of the study to provide additional protection for the research participants and their subsequently generated data on genetic markers.
