[1] Ctr Res Excellence Severe Asthma, New Lambton, NSW, Australia
[2] Univ Newcastle, Sch Nursing & Midwifery, Newcastle, NSW, Australia
[3] John Hunter Hosp, Dept Resp & Sleep Med, New Lambton Hts, NSW, Australia
[4] Univ Newcastle, Prior Res Ctr Hlth Lungs, Newcastle, NSW, Australia