Abstract
Frailty is a clinical syndrome observed in older adults that associates with poor health outcomes. Despite the attempt to standardize its definition and clinical features, the complexity and the multiplicity of the physiologic dysregulations observed in frailty have led to the development of innumerous assessment tools. Herein, we highlight frequently used assessment tools for frailty describing the criteria, pros and cons regarding clinical feasibility, reliability, and validity as well as risk predictability. We further compare the 2 well-established landmark frailty assessment tools, the Physical Frailty Phenotype and the Frailty Index, in an attempt to unravel how such distinct methodologies prevail as the most commonly used clinical tools to prevent adverse outcomes worldwide.