The predictive validity of the Tilburg Frailty Indicator: disability, health care utilization, and quality of life in a population at risk.
OBJECTIVE
To assess the predictive validity of frailty and its domains (physical, psychological, and social), as measured by the Tilburg Frailty Indicator (TFI), for the adverse outcomes disability, health care utilization, and quality of life.


METHODS
The predictive validity of the TFI was tested in a representative sample of 484 community-dwelling persons aged 75 years and older in 2008 (response rate 42%). A subset of all respondents participated 1 year later (N = 336, 69%) and again 2 years later (N = 266, 55%). We used the TFI, the Groningen Activity Restriction Scale assessing disability, seven indicators of health care utilization, and a brief version of the World Health Organization Quality of Life questionnaire (WHOQOL-BREF). The WHOQOL-BREF was assessed in 2008 and 2010; all others were assessed in 2008, 2009, and 2010.


RESULTS
The predictive validity of the TFI assessed in 2008 for disability, health care utilization, and quality of life was corroborated by (a) medium to very large associations of frailty with adverse outcomes 1 or 2 years later; (b) mostly good to excellent area under the curve of total frailty; and (c) an increase in predictive accuracy of most adverse outcomes, even after controlling for that same adverse outcome in 2008, and life-course determinants and multimorbidity. Physical frailty was mostly responsible for the predictive validity of the TFI.


CONCLUSIONS
This study showed that the TFI is a valid instrument to predict disability, many indicators of health care utilization, and quality of life of older people, 1 and 2 years later.
Rotterdam University of Applied Sciences, Museumpark 40, 3015 CX Rotterdam, The Netherlands. gobrj@hr.nl
Robbert J J
RJ
Gobbens
Marcel A L M
MA
van Assen
Katrien G
KG
Luijkx
Jos M G A
JM
Schols
D000368:Aged; D000369:Aged, 80 and over; D004185:Disability Evaluation; D006233:Persons with Disabilities; D005260:Female; D016330:Frail Elderly / Q000523:psychology*; D015577:Geriatric Assessment / Q000379:methods / Q000706:statistics & numerical data*; D006296:Health Services / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009426:Netherlands; D011237:Predictive Value of Tests; D011320:Primary Health Care / Q000706:statistics & numerical data; D011594:Psychometrics / Q000706:statistics & numerical data; D011788:Quality of Life / Q000523:psychology*; D012044:Regression Analysis; D015203:Reproducibility of Results; D012306:Risk; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards; D035862:Vulnerable Populations; D014944:World Health Organization