“…Eight studies 26 , 27 , 28 , 29 , 30 , 34 , 36 , 38 used advanced diseases with a life expectancy less than 1 year, such as metastatic cancer, end-stage congestive heart, or renal failure, as the inclusion criteria, while 7 studies 31 , 32 , 33 , 35 , 37 , 39 , 40 had no exclusion criteria based on illness. The mean age of the study population was 60 years or older in 12 studies.…”