1. Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Mexico
2. Department of Pulmonary Medicine and
3. Department of Pulmonary Medicine, Cleveland Clinic, Cleveland, Ohio
4. Department of Pulmonary and Critical Care Medicine, Henry Ford Hospital, Detroit, Michigan
5. Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, Maryland; and
6. Division of Pulmonary and Critical Care Medicine, University Hospitals, Cleveland, Ohio
7. Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas