1 Division for Health Services, Norwegian Institute of Public Health, Oslo, Norway.
2 Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Medicine, Østfold Hospital Trust, Grålum. Norway; Department of Research, Østfold Hospital Trust, Grålum, Norway.
3 Division for Health Services, Norwegian Institute of Public Health, Oslo, Norway; Department of Pulmonary Medicine, Division of Medicine, Akershus University Hospital, Sykehusveien 25, 1478 Lørenskog, Norway.
4 Division for Health Services, Norwegian Institute of Public Health, Oslo, Norway; Department of Pulmonary Medicine, Division of Medicine, Akershus University Hospital, Sykehusveien 25, 1478 Lørenskog, Norway; Health Services Research Unit, Akershus University Hospital, Lørenskog, Norway. Electronic address: [email protected].