1 Division of Transplantation, Department of Surgery, Leiden University Medical Center, Leiden University, Leiden, The Netherlands.
2 Eurotransplant International Foundation, Leiden, The Netherlands.
3 Section of Gerontology and Geriatrics, Department of Internal Medicine, Leiden University Medical Center, Leiden University, Leiden, The Netherlands.
4 Department of Gastroenterology and Hepatology, Erasmus MC - University Medical Center, Rotterdam, The Netherlands.