Prognosis requires objective assessment of a milieu of findings that are beyond any health care provider or statistical tool to accomplish. For some time now phase angle determined by bioelectrical impedance has been shown to be reliable, accurate and objective to assess the presence, progression and severity of disease, measure the effectiveness of treatment and predict the timing of non-acute death. Specifically for your type of patient here is a good reference, Bioelectrical phase angle values in a clinical sample of ambulatory rehabilitation patients Simon M Gunn, et al. Dynamic Medicine 2008, 7:14 doi:10.1186/1476-5918-7-14 There are many others, good luck, Cheers! Michaeal