During the last century the considerable increase in life expectancy has led to important demographic changes and, consequently, to new clinical scenarios. Nowadays, chronic conditions, comorbidities and socio-economic factors constitute a relevant health management issue. In particular, the definition of frail elderly individuals has proven to have a strong role in the identification of high-risk patients, their clinical management and prognosis. Reorganization of the medical system has been associated with the development of new instruments for clinical assessment, focused on clinical and socio-economic issues, resulting in a multidimensional geriatric assessment. A large number of approaches have been validated in different clinical settings and populations, until the development of multidimensional instruments demonstrated to have a crucial role in the identification of frail individuals and in their clinical management. Interestingly, some of these, such as the Multidimensional Prognostic Index (MPI), proved to play a relevant role in mortality risk stratification even in particular clinical settings such as chronic kidney disease.