[1] Ludwig Boltzmann Inst Lung Hlth, Vienna, Austria
[2] Maastricht Univ, Care & Publ Hlth Res Inst, Maastricht, Netherlands
[3] Sigmund Freud Univ, Fac Med, Vienna, Austria
[4] Maastricht Univ, Dept Hlth Serv Res, Maastricht, Netherlands
[5] Care & Publ Hlth Res Inst, Dept Family Med, Maastricht, Netherlands
[6] Ciro, Dept Res & Dev, Horn, Netherlands
[7] Imperial Coll London, Natl Heart & Lung Inst, London, England
[8] Imperial Coll London, NIHR Imperial Biomed Res Ctr, London, England