Conceptualisation and Measurement of Frailty in Elderly People Kenneth Rockwood, 1 David B. Hogan 2 and Chris MacKnight 1 1 Division of Geriatric Medicine, Dalhousie University, Halifax, Nova Scotia, Canada 2 Division of Geriatric Medicine, University of Calgary, Calgary, Alberta, Canada Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 1. Frailty and Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296 2. Frailty and Disability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297 3. Defining Frailty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298 4. Measures of Frailty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 5. Critique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 Abstract The use of the term ‘frailty’ has shown tremendous growth in the last 15 years, but this has not been accompanied by a widely accepted definition, let alone agreed-upon measures. In this paper, we review approaches to the definition and measurement of frailty and discuss the relationship between frailty, aging and disability. Two trends are evident in definitions, which often trade off compre- hensiveness for precision: frailty can be seen as being synonymous with a single- system problem or as a multisystem problem. The essential feature of frailty is the notion of risk due to instability (itself suggesting a balance of many factors), and has been only poorly measured to date. Future models of frailty should in- corporate more precise operationalisation of the probability of frailty and better explain the relationship between disease, disability and frailty. REVIEW ARTICLE Drugs & Aging 2000 Oct; 17 (4): 295-302 1170-229X/00/0010-0295/$20.00/0 © Adis International Limited. All rights reserved. Elderly people have a variety of healthcare needs, which are pressing on every healthcare sys- tem worldwide. Summarising needs is a helpful prelude to devising, implementing and evaluating responses. Often, what makes the needs of elderly people particular is their multiplicity, and a blur- ring between problems otherwise easily charac- terised as ‘medical’ or ‘social’. In this context, the construct of frailty has been proposed as a way to better understand the health needs of elderly people. Frailty is a term that has enjoyed substantial growth since the 1980s, but it often remains unde- fined. [1,2] Even when defined, it is evident that different authors emphasise different aspects of frailty. As reviewed elsewhere, [3] the notion of frailty has included the notions of: • being dependent on others • being at a substantial risk of dependency and other adverse health outcomes • experiencing the loss of ‘physiological re- serves’ • experiencing ‘uncoupling from the environ- ment’ [4] • having many chronic illnesses • having complex medical and psychosocial problems • having ‘atypical’ disease presentations