A comparison of four frailty models

Abstract

Objectives: To determine how well the interview-based, clinic-friendly International Academy of Nutrition and Aging (FRAIL) frailty scale predicts future disability and mortality in the African American Health (AAH) cohort compared with the clinic-friendly Study of Osteoporotic Fractures (SOF) frailty scale, the phenotype-based Cardiovascular Health Study (CHS) frailty scale, and the comprehensive Frailty Index (FI).

Design: Longitudinal cohort study.

Setting: Metropolitan St. Louis, Missouri.

Participants: African American Health is a population-based panel study of African Americans (baseline age 49-65) from St. Louis, Missouri. Participants completed in-home assessments at baseline (N = 998) and 3- (n = 853) and 9- (n = 582) year follow-up.

Measurements: Outcomes included activity of daily living (ADL) and instrumental ADL difficulties at 3 and 9 years and 9-year mortality. Frailty measures included the FRAIL, SOF, and CHS scales and the FI.

Results: The FRAIL, SOF, CHS, and FI measures predicted new 3- and 9-year disability, and the FRAIL and FI scales predicted 9-year mortality. Receiver operating characteristic (ROC) contrasts showed that the FRAIL scale performed as well as (9-year disability and mortality) or better than (3-year disability) the CHS and SOF scales and the FI better than the FRAIL, CHS, and SOF scales for all outcomes except the FRAIL and CHS scales for 9-year ADL difficulties. The CHS and SOF scales were equivalent for all outcomes in ROC contrasts.

Conclusion: Overall the FI and the FRAIL scale exhibited the strongest predictive validity for disability and mortality in AAH. The best prediction tool to identify frail individuals at risk of disability and mortality may be one that includes a comorbidity measure. The FRAIL scale includes a comorbidity item and is a brief interview-based measure that is easy to administer, score, and interpret. The FRAIL scale has demonstrated validity and may prove to be a valuable scale for use by clinicians.

Keywords: ADLs; African American; IADLs; frailty; mortality.

© 2014, Copyright the Authors Journal compilation © 2014, The American Geriatrics Society.

Figures

Figure 1

(A) One or more new activity of daily living (ADL) difficulties at 3 years. Receiver operating characteristic (ROC) contrasts: Frailty Index (FI) versus International Academy of Nutrition and Aging (FRAIL) frailty scale, P = .047; FI versus Cardiovascular Health Study (CHS) frailty scale, P < .001; FI versus Study of Osteoporotic Fractures (SOF) frailty scale, P < .001; FRAIL scale versus CHS scale, P = .002; FRAIL scale versus SOF scale, P < .001; CHS scale versus SOF scale, P = .62. (B) One or more new ADL difficulties at 9 years. ROC contrasts: FI versus SOF scale, P = .03; FRAIL scale versus SOF scale, P = .03; FI versus FRAIL scale, P = .71; FI versus CHS scale, P = .22; FRAIL versus CHS scale, P = .31; CHS scale versus SOF scale, P = .30. (C) One or more new instrumental activity of daily living (IADL) difficulties at 3 years. ROC contrasts: FI versus FRAIL scale, P < .001; FI versus CHS scale, P < .001; FI versus SOF scale, P < .001; FRAIL scale versus CHS scale, P = .02; FRAIL scale versus SOF scale, P < .001; CHS scale versus SOF scale, P = .40. (D) One or more new IADL difficulties at 9 years. ROC contrasts: FI versus FRAIL scale, P = .001; FI versus CHS scale, P < .001; FI versus SOF scale, P = .01; FRAIL scale versus CHS scale, P = .38, FRAIL scale versus SOF scale, P = .72; CHS scale versus SOF scale, P = .28. (E) 9-year mortality. ROC contrasts: FI versus FRAIL scale, P = .001; FI versus CHS scale, P = <.001; FI versus SOF scale, P = <.001; FRAIL scale versus CHS scale, P = .22; FRAIL scale versus SOF scale, P = .10; CHS scale versus SOF scale, P = .92.