Purpose: 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.
Design and 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.
Implications: 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.