Frailty and sarcopenia: From theory to clinical implementation and public health relevance.

The sustainability of healthcare systems is threatened by the increasing (absolute and relative) number of older persons referring to clinical services. Such global phenomenon is questioning the traditional paradigms of medicine, pushing towards the need of new criteria at the basis of clinical decision algorithms. In this context, frailty has been advocated as a geriatric condition potentially capable of overcoming the weakness of chronological age in the identification of individuals requiring adapted care due to their increased vulnerability to stressors. Interestingly, frailty poses itself beyond the concept of nosological conditions due to the difficulties at correctly framing traditional diseases in the complex and heterogeneous scenario of elders. Thus, frailty may play a key role in public health policies for promoting integrated care towards biologically aged individuals, currently presenting multiple unmet clinical needs. At the same time, the term frailty has also been frequently used in the literature for framing a physical condition of risk for (mainly functional) negative endpoints. The combination of such physical impairment with an organ-specific phenotype (e.g., the age-related skeletal muscle decline or sarcopenia) may determine the assumptions for the development of a clinical condition to be used as potential target for ad hoc interventions against physical disability. In the present article, we present the background of frailty and sarcopenia, and discuss their potentialities for reshaping current clinical and research practice in order to promote holistic approach to older patients, solicit personalization of care, and develop new targets for innovative interventions.