How to construct a frailty index from an existing dataset in 10 steps.

TitleHow to construct a frailty index from an existing dataset in 10 steps.
Publication TypeJournal Article
Year of Publication2023
AuthorsTheou, O, Haviva, C, Wallace, L, Searle, SD, Rockwood, K
JournalAge and Ageing
ISSN Number1468-2834
KeywordsAged, Aging, Frail Elderly, Frailty, Geriatric Assessment, Humans, Retrospective Studies

BACKGROUND: The frailty index is commonly used in research and clinical practice to quantify health. Using a health deficit accumulation model, a frailty index can be calculated retrospectively from data collected via survey, interview, performance test, laboratory report, clinical or administrative medical record, or any combination of these. Here, we offer a detailed 10-step approach to frailty index creation, with a worked example.

METHODS: We identified 10 steps to guide the creation of a valid and reliable frailty index. We then used data from waves 5 to 12 of the Health and Retirement Study (HRS) to illustrate the steps.

RESULTS: The 10 steps are as follows: (1) select every variable that measures a health problem; (2) exclude variables with more than 5% missing values; (3) recode the responses to 0 (no deficit) through 1 (deficit); (4) exclude variables when coded deficits are too rare (< 1%) or too common (> 80%); (5) screen the variables for association with age; (6) screen the variables for correlation with each other; (7) count the variables retained; (8) calculate the frailty index scores; (9) test the characteristics of the frailty index; (10) use the frailty index in analyses. In our worked example, we created a 61-item frailty index following these 10 steps.

CONCLUSIONS: This 10-step procedure can be used as a template to create one continuous health variable. The resulting high-information variable is suitable for use as an exposure, predictor or control variable, or an outcome measure of overall health and ageing.

Citation Key13788
PubMed ID38124255
PubMed Central IDPMC10733590
Grant ListR03 AG043052 / AG / NIA NIH HHS / United States
NIA U01AG009740 / AG / NIA NIH HHS / United States