Operationalization of the physical frailty & sarcopenia syndrome: rationale and clinical implementation.

Over the years, different operational definitions have been elaborated to identify frail older persons, but none of them has received unanimous consensus. This, in turn, has hampered the clinical implementation of frailty as well as the design of targeted interventions. To overcome the current limitations in the field, a novel operationalization of physical frailty (PF) is proposed which grounds its roots in the recognition of sarcopenia as its central biological substrate. This conceptualization is based on the fact that the clinical picture of PF overlaps substantially with that of sarcopenia. The two conditions may therefore be merged into a new clinical entity, the PF & sarcopenia (PF&S) syndrome, in which muscle loss represents both the biological substrate for the development of PF and a major pathway whereby the negative health outcomes of PF occur. All of the components defining the PF&S syndrome are measurable in an objective manner, which will facilitate its incorporation into standard practice. The recognition of a precise biological substratum for PF&S (i.e., skeletal muscle decline) also opens new venues for the development of preventive and therapeutic interventions.