PMC

Survival curves smoothed by Cox regression for each of the 9 selected sub-groups defined on the basis of categorization of the phenotypic frailty index (PFI) and deficit index (DI) into 3 categories (see ) as robust, pre-frail, and frail: 1) PFI3^robust and DI3^robust; 2) PFI3^robust and DI3^pre-frail; 3) PFI3^robust and DI3^frail; 4) PFI3^pre-frail and DI3^robust; 5) PFI3^pre-frail and DI3^pre-frail; 6) PFI3^pre-frail and DI3^frail; 7) PFI3^frail and DI3^robust; 8) PFI3^frail and DI3^pre-frail; and 9) PFI3^frail and DI3^frail.