title: Measuring frailty using self-report and test-based health measures.
abstract: BACKGROUND
  previously, frailty indices were constructed using mostly subjective health measures. The reporting error in this type of measure can have implications on the robustness of frailty findings.
  
  
  OBJECTIVE
  to examine whether frailty assessment differs when we construct frailty indices using solely self-reported or test-based health measures.
  
  
  METHODS
  secondary analysis of data from The Irish LongituDinal study on Ageing (TILDA).
  
  
  METHODS
  4,961 Irish residents (mean age: 61.9 ± 8.4; 54.2% women) over the age of 50 years who underwent a health assessment were included in this analysis. We constructed three frailty indices using 33 self-reported health measures (SRFI), 33 test-based health measures (TBFI) and all 66 measures combined (CFI). The 2-year follow-up outcomes examined were all-cause mortality, disability, hospitalisation and falls.
  
  
  RESULTS
  all three indices had a right-skewed distribution, an upper limit to frailty, a non-linear increase with age, and had a dose-response relationship with adverse outcomes. Levels of frailty were lower when self-reported items were used (SRFI: 0.12 ± 0.09; TBFI: 0.17 ± 0.15; CFI: 0.14 ± 0.13). Men had slightly higher frailty index scores than women when test-based measures were used (men: 0.17 ± 0.09; women: 0.16 ± 0.10). CFI had the strongest prediction for risk of adverse outcomes (ROC: 0.64-0.81), and age was not a significant predictor when it was included in the regression model.
  
  
  CONCLUSIONS
  except for sex differences, characteristics of frailty are similar regardless of whether self-reported or test-based measures are used exclusively to construct a frailty index. Where available, self-reported and test-based measures should be combined when trying to identify levels of frailty.
authors: Dalhousie University, Geriatric Medicine, Veterans' Memorial Building, 5955 Veterans' Memorial Lane, Halifax, Nova Scotia B3H2E1, Canada.
authors: O
authors: O
authors: Theou
authors: The Irish Longitudinal Study on Ageing, Department of Medical Gerontology, Trinity College, Dublin 2, Ireland.
authors: M D L
authors: MD
authors: O'Connell
authors: The Irish Longitudinal Study on Ageing, Department of Medical Gerontology, Trinity College, Dublin 2, Ireland.
authors: B L
authors: BL
authors: King-Kallimanis
authors: The Irish Longitudinal Study on Ageing, Department of Medical Gerontology, Trinity College, Dublin 2, Ireland.
authors: A M
authors: AM
authors: O'Halloran
authors: Dalhousie University, Geriatric Medicine, Veterans' Memorial Building, 5955 Veterans' Memorial Lane, Halifax, Nova Scotia B3H2E1, Canada.
authors: K
authors: K
authors: Rockwood
authors: The Irish Longitudinal Study on Ageing, Department of Medical Gerontology, Trinity College, Dublin 2, Ireland Mercer's Institute for Successful Ageing, St. James's Hospital, Dublin 8, Ireland.
authors: R A
authors: RA
authors: Kenny
mesh_terms: D000368:Aged; D000375:Aging; D005260:Female; D016330:Frail Elderly / Q000706:statistics & numerical data; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D057566:Self Report; D012737:Sex Factors
keywords: frailty; frailty index; older people; self-reported health measures; test-based health measures