[1] Sir Charles Gairdner Hosp, Dept Resp Med, Perth, WA, Australia
[2] Univ Western Australia, Sch Med & Pharmacol, Perth, WA 6009, Australia
[3] Lung Inst Western Australia, Perth, WA, Australia
[4] Sutherland Hosp, Dept Resp & Sleep Med, Sydney, NSW, Australia
[5] St George Hosp, Dept Resp Med, Sydney, NSW, Australia
[6] Middlemore Hosp, Dept Resp Med, Auckland 6, New Zealand
[7] Natl Univ Singapore, Yong Loo Lin Med Sch, Natl Univ Hosp, Div Resp & Crit Care Med,Dept Med, Singapore 117548, Singapore
[8] Swan Dist Hosp, Dept Internal Med, Perth, WA, Australia
[9] Fremantle Hosp, Dept Resp Med, Fremantle, WA, Australia
[10] Princess Alexandra Hosp, Dept Resp & Sleep Med, Brisbane, Qld 4102, Australia
[11] Univ Hong Kong, Dept Med, Kong, Peoples R China
[12] Univ Queensland, Sch Med, Brisbane, Qld, Australia
[13] Holy Spirit Northside Hosp, Brisbane, Qld, Australia
[14] Nambour Gen Hosp, Dept Resp Med, Sunshine Coast, Qld, Australia
[15] Univ Western Australia, Ctr Appl Stat, Perth, WA 6009, Australia
[16] Wellington Hosp, Med Res Inst New Zealand, Wellington, New Zealand