Works the other way too. Early recovery portends a better prognosis. Holds for bed mobility with hospitalisation
Hatheway OL, et al., Frailty affects the initial treatment response and time to recovery of mobility in acutely ill older adults... Age Ageing. 2017;46:920-5 and in/
The longer someone is unwell for, without improvement, and the more illnesses they develop, the lower their chances of recovery. Remember frailty is about deficit accumulation as much as phenotype. Accumulating lots of deficits in a short period is a bad sign