[1] Univ Zurich Hosp, Div Pulm, Dept Internal Med, CH-8091 Zurich, Switzerland
[2] Inst Hausarztmed, Zurich, Switzerland
[3] Luzerner Hohenklin, Montana, Switzerland
[4] Kantonsspital St Gallen, St Gallen, Switzerland
[5] Klin Barmelweid, Barmelweid, Switzerland
[6] Kantonsspital Graubunden, Chur, Switzerland
[7] Osped Reg Bellinzona & Valli, Bellinzona, Switzerland
[8] Univ Lausanne Hosp, Div Pulm, Lausanne, Switzerland
[9] Univ Hosp Bern, Div Pulm, CH-3010 Bern, Switzerland
[10] Univ Hosp, Div Pulm, Geneva, Switzerland
[11] Univ Basel Hosp, Div Pulm, CH-4031 Basel, Switzerland