[1] Univ Iowa, Pulm & Crit Care, Iowa City, IA USA
[2] Univ Iowa, Natl Jewish Hlth, Dept Med 3, Iowa City, IA 52242 USA
[3] Univ Alabama Birmingham, Pulm Allergy & Crit Care Med, Birmingham, AL USA
[4] Univ Iowa, Inst Clin & Translat Sci, Biostat & Res Design, Iowa City, IA USA
[5] Univ Texas Austin, Pulm & Crit Care, Austin, TX USA
[6] Univ Michigan, Sch Med, Ann Arbor, MI USA
[7] Univ Colorado Denver, Colorado Sch Publ Hlth, Dept Epidemiol, Aurora, CO USA
[8] Univ Colorado, Colorado Sch Publ Hlth, Epidemiol, Aurora, CO USA
[9] Univ Michigan Hlth Syst, Internal Med, Ann Arbor, MI USA
[10] Natl Jewish Hlth, Denver, CO USA
[11] VA Boston Healthcare Syst, Boston, MA USA
[12] Pulm & Sleep 111N, Minneapolis, VA USA
[13] Univ Minnesota, Med, Minneapolis, MN USA
[14] Minneapolis VAMC, Minneapolis, MN USA
[15] Natl Jewish Hlth, Denver, CO USA
[16] Univ Alabama Birmingham, Birmingham, AL USA
[17] Birmingham VA Med Ctr, Birmingham, AL USA
[18] Natl Jewish Hlth, Med, Denver, CO USA
[19] Brigham & Womens Hosp, Boston, MA USA
[20] Univ Iowa, Internal Med Pulm, Iowa City, IA USA