Definitions and markers of frailty: a systematic review of literature

Frailty is a central concept in geriatric medicine, but without a clear definition. Many regard it as a syndrome with its own clinical manifestations and pathophysiology, whilst others consider it to be the result of the accumulation of age-related deficits that predict adverse changes in health. We analysed, through a systematic review, the definitions and markers of the frailty syndrome. Twenty-five articles were included and divided, according to design, into observational, intervention, review and qualitative studies. There was a predominance of operational definitions that used only physical markers to identify frailty. The only qualitative study found that health professionals chose a multidimensional definition that took into account factors other than just the physical. We conclude that there is still no standard definition or agreement about markers of the frailty syndrome.