Overall only a few studies are done on tube feeding (TF) in older adults with the aim of improving nutritional status. Regarding RFS and older adults, there are only six clinical trials, but none of them RCT`s. These trials are mostly looking at occurrence of RFS, and they all use different cut off levels when defining hypophosphatemia (HP). In addition, they all used different outcomes measures; either mortality rates, delirium or muscle strength, which in the end makes it difficult to compare the studies.