[1] Med Spectrum Twente, Dept Pulm Med, Haaksbergerstr 55, NL-7513 ER Enschede, Netherlands
[2] Repatriat Gen Hosp, Southern Adelaide Local Hlth Network, Resp Res Unit, Daw Pk, SA, Australia
[3] Flinders Univ S Australia, Sch Med, Adelaide, SA 5001, Australia
[4] Univ Groningen, Univ Med Ctr Groningen, Dept Pulmonol, NL-9713 AV Groningen, Netherlands
[5] Radboud Univ Nijmegen, Med Ctr, Dept Hlth Evidence, NL-6525 ED Nijmegen, Netherlands
[6] Univ Twente, Dept Res Methodol Measurement & Data Anal, POB 217, NL-7500 AE Enschede, Netherlands