Transitions, Trajectories, and Reversibility

Frailty is a dynamic process that can vary widely between individuals and populations. Longitudinal studies have identified patterns of frailty change that include progression, plateaus, and reversal. Yet, patterns of change may depend on the frailty measure used (i.e., the cumulative deficit model vs the physical phenotype), the method of analyzing change, and the population being studied. In this chapter, we review how change in frailty can be measured, patterns that have been identified, how these trajectories may differ at end of life and in specific disease states, risk factors for progression, and potential strategies that may reverse frailty.