[1] University Hospital Erlangen,Division of Palliative Medicine
[2] RWTH Aachen University,Department of Palliative Medicine
[3] RWTH Aachen University,Institute of Hygiene and Environmental Medicine
[4] University Hospital Bonn,Department of Palliative Medicine
[5] Centre of Palliative Medicine,undefined
[6] Malteser Hospital Bonn,undefined