“…Four were carried out in the United Kingdom [ 27 , 31 , 34 , 38 ], one in Spain [ 17 ], and one in Turkey [ 36 ]. Of the 19 studies, seven were conducted in the elderly [ 24 , 27 , 29 , 30 , 34 , 38 , 39 ], six in patients with heart failure [ 16 , 17 , 26 , 33 , 37 , 40 ], one in chronic kidney disease patients [ 31 ], one in cardiovascular disease patients [ 28 ], one in chronic hemodialysis patients [ 25 ], one in kidney transplant candidates [ 32 ], one in palliative care patients [ 36 ], and one in male veterans [ 35 ]. The length of follow-up ranged from 3 months to 8 years (one study [ 31 ] did not provide data on follow-up period).…”