Incidence of frailty: a systematic review of scientific literature from a public health perspective

Because of the dynamic nature of frailty, prospective epidemiological data are essential to calibrate an adequate public health response.A systematic review of literature on frailty incidence was conducted within the European Joint Action ADVANTAGE.Of the 6 studies included, only 3 were specifically aimed at estimating frailty incidence, and only 2 provided disaggregated results by at least gender. The mean follow-up length (1-22.2 years; median 5.1), sample size (74-6306 individuals), and age of participants (≥ 30-65) varied greatly across studies. The adoption of incidence proportions rather than rates further limited comparability of results. After removing one outlier, incidence ranged from 5% (follow-up 22.2 years; age ≥ 30) to 13% (follow-up 1 year, age ≥ 55).Well-designed prospective studies of frailty are necessary. To facilitate comparison across studies and over time, incidence should be estimated in person-time rate. Analyses of factors associated with the development of frailty are needed to identify high-risk groups.