[1] Univ Oslo, Dept Hlth Management & Hlth Econ, Oslo, Norway
[2] Fresenius Med Care, Market Access & Hlth Econ, Bad Homburg, Germany
[3] Fresenius Med Care UK Ltd, Hlth Econ, Market Access & Prod Management, Huthwaite, England
[4] Univ Oslo, Dept Hlth Management & Hlth Econ, POB 1089 Blindern, Oslo 0317, Norway