Deficit-Accumulation Frailty Index

The deficit-accumulation frailty index measures frailty as the proportion of a long list of age-related health deficits that a person has accumulated. Introduced by Arnold Mitnitski and Kenneth Rockwood in 2001, it treats frailty not as a fixed syndrome but as a quantitative state: the more things have gone wrong across many body systems, the frailer the person. Counting 30 or more deficits — symptoms, signs, diseases, disabilities, and laboratory abnormalities — and dividing by the number considered yields a continuous score between 0 and 1 that rises with age, predicts mortality and adverse outcomes, and behaves remarkably consistently regardless of exactly which deficits are used. A standardized procedure by Searle and colleagues made the index easy to construct from existing data.