[1] Univ Hosp Leuven, Dept Geriatr Med, Leuven, Belgium
[2] Univ Hosp Leuven, Dept Abdominal Surg, Leuven, Belgium
[3] Univ Hosp Leuven, Dept Anesthesia, Leuven, Belgium
[4] Katholieke Univ Leuven, Dept Publ Hlth & Primary Care, Div Gerontol & Geriatr, Leuven, Belgium
[5] Univ Basel, Inst Nursing Sci, Dept Publ Hlth, Basel, Switzerland