Searching for an Operational Definition of Frailty: A Delphi Method Based Consensus Statement. The Frailty Operative Definition-Consensus Conference Project

The concept of frailty has grown in importance because of a need for a better understanding of the health and functional status of older persons and a need to prevent or at least delay the onset of late-life disability and its adverse consequences (1). There is to date no clear consensus regarding the definition of frailty (2,3). The most frequently used definition (4) is focused on the evaluation of five domains (nutritional status, energy, physical activity, mobility, and strength) and has established five criteria (one per each domain: weight loss, exhaustion, leisure time activity, gait speed, and grip strength, respectively) for defining the frail phenotype and for identifying older persons at elevated risk for numerous adverse outcomes. However, other definitions have been proposed, each with their own strengths and weaknesses (5). In addition to assessing physical functioning, many researchers believe that frailty definitions should also include domains, such as cognition, mood, and other aspects of mental health (6,7). Frailty definitions should be validated in a wide variety of cultural, economic, ethnic, and clinical settings (8) and demonstrate the predictive validity of frailty for adverse outcomes (9,10). The diagnosis of frailty relies currently on the assessment of a relatively small subset of easily measurable clinical markers (eg, Fried Criteria). While recognizing the multifactorial nature of frailty, it is important to develop an “operational definition” of frailty that is simple enough to be used clinically and to guide prevention and care. A working group of experts from a variety of fields related to frailty were invited to participate in a collaborative project, with the aim of developing the most complete and concrete definition of frailty possible.