Distinguishing Comorbidity, Disability, and Frailty.

PURPOSE OF REVIEW: Over half of the older adults in U.S. have multimorbidity, defined broadly as the presence of 2 or more chronic diseases in an individual. Multimorbidity has significant overlap with disability and frailty. In this review, we broadly review the concepts of multimorbidity, disability, and frailty, as well as their interrelationships, and ability to predict future adverse health outcomes in older adults. RECENT FINDINGS: Depending on the study, the prevalence of individuals with all three of multimorbidity, disability, and frailty ranges from 2-20%. Multimorbidity and patterns of multimorbidity are predictive of functional limitations, disability, health care usage, and mortality. The degree to which multimorbidity predicts these outcomes depends on many factors but partly upon the population examined and the presence of frailty and disability. SUMMARY: Multimorbidity is an emerging public health concern that is observed with and predictive of disability and frailty.