[1] Mt Auburn Hosp, Dept Med, Cambridge, MA 02138 USA
[2] Harvard Med Sch, Boston, MA USA
[3] Imperial Coll London, Dept Surg & Canc, London, England
[4] Med Data Res Collaborat, London, England
[5] Imperial Coll Healthcare NHS Trust, Dept Resp Med, London, England
[6] Imperial Coll London, Natl Heart & Lung Inst, London, England
[7] Brigham & Womens Hosp, Pulm & Crit Care Med, Boston, MA USA
[8] Massachusetts Gen Hosp, Dept Med, Div Rheumatol Allergy & Immunol, Boston, MA USA
[9] Mt Auburn Hosp, Dept Med & Med Educ, 300 Mt Auburn St, Cambridge, MA 02138 USA