[1] Univ Iowa, Dept Psychiat, Iowa City, IA 52242 USA
[2] Univ Iowa, Dept Internal Med, Iowa City, IA USA
[3] Natl Jewish Hlth, Div Rheumatol, Denver, CO USA
[4] Natl Jewish Hlth, Div Pulm Crit Care & Sleep, Dept Med, Denver, CO USA
[5] Natl Jewish Hlth, Dept Med, Div Neurol & Behav Hlth, Denver, CO USA
[6] Univ Colorado, Dept Med, Div Pulm Sci & Crit Care Med, Sch Med, Aurora, CO USA
[7] Univ Michigan, Dept Internal Med, Div Pulm & Crit Care Med, Ann Arbor, MI USA
[8] Morehouse Sch Med, Pulm & Crit Care Med Div, Atlanta, GA USA
[9] Univ Alabama Birmingham, Dept Med, Div Pulm Allergy & Crit Care Med, Birmingham, AL USA
[10] Univ Ottawa, Lewis Katz Sch Med, Dept Thorac Med & Surg, Philadelphia, PA USA
[11] Univ Pittsburgh, Dept Med, Div Pulm Allergy & Crit Care Med, Pittsburgh, PA USA
[12] VA Pittsburgh Healthcare Syst, Pittsburgh, PA USA
[13] Univ Calif San Diego, Dept Pulm Crit Care & Sleep Med, San Diego, CA USA
[14] Univ Colorado, Colorado Sch Publ Hlth, Dept Epidemiol, Aurora, CO USA
[15] Univ Colorado, Colorado Sch Publ Hlth, Dept Community & Behav Hlth, Aurora, CO USA
[16] Baylor Coll Med, Sect Pulm & Crit Care Med, Houston, TX USA
[17] Case Western Reserve Univ, Sch Med, Cleveland, OH USA
[18] Azusa Pacific Univ, Dept Phys Therapy, Azusa, CA USA
[19] Stanford Univ, Dept Psychiat & Behav Sci, Sch Med, Palo Alto, CA USA
[20] Univ Iowa, Iowa Neurosci Inst, Iowa City, IA USA
[21] Ottawa Hosp, Ottawa Hosp Res Inst, Ottawa, ON, Canada