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

This study aimed to review and extract all publications containing concepts related to definitions of frailty and categorize them.

A total of six electronic databases (PubMed, Ovid web, Web of Science, Scopus, Embase, Cochrane Library, and ProQuest) were searched to identify studies that introduced a definition of frailty up to October 2018. No language restrictions were imposed.

Totally, 104,370 papers were found in the initial search and finally 68 papers were included. Of these, 21 studies provided a conceptual definition and 50 original articles also 9 review articles provided a practical definition. Moreover, 12 papers had both definitions of frailty. Of them, 62 were published in English, 2 in Portuguese, 1 in Japanese, 2 in Korean, and 1 in German languages.

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.