The conceptual and practical definitions of frailty in older adults: a systematic review.

Many screening tools have been developed but neither of them can cover a wide range of parameters at the same time, nor do they have simplicity in the execution. It is important to note that although a more or less general consensus on one single definition might be expected, we believe that the elderly population is too heterogeneous to allow a tool to address it as a whole, and such a definition may even be impossible. Therefore, in the absence of a "Gold Standard" definition, it is suggested to seek accurate knowledge of the strengths and weaknesses of each definition and choose the most appropriate definition and the most effective evaluation tool according to the purpose of the research and the characteristics of the older population.