Validity and Reliability of the Polish Version of the Tilburg Frailty Indicator (TFI)

In the last decade, studies on frailty have become increasingly frequent in the literature on aging, and also the number of available questionnaires regarding frailty has increased over the years. Therefore, the choice of which questionnaire to use is becoming more difficult.

The aim of this study was to assess the psychometric properties of the Polish version of the Tilburg Frailty Indicator (TFI), an instrument that identifies frailty in the elderly population.

Setting, and Participants. The study was carried out in a community-based setting in Wrocław, Poland. Nurses and doctors (general practitioners) administered the TFI in primary care facilities. Participants included a sample of 212 community dwelling elderly aged 60 or older (mean age:70.6 SD≥7.16).

The validation (assessment of face validity, content validity) was carried out in accordance with the literature. The Tilburg Frailty Indicator (TFI) consists of two different parts. One part addresses the potential determinants of frailty and the other specifically addresses the components of frailty, covering its physical, psychological and social domains. Scale reliability was estimated using two methods: Cronbach's alpha, measuring the scale's internal consistency, and the test-retest method, determining the scale's absolute stability. To assess test-retest reliability, the same group was re-interviewed by the same observer within 10-14 days of the first interview.

The test-retest reliability showed a high level of agreement for all items of the instrument, with values ranging from 96 to 100%. The Cronbach's Alpha internal consistency was 0.74.

The Polish version of the TFI proved to be a valid and reproducible tool for assessment of Frailty Syndrome for the Polish population. We would recommend to be used as the screening tool to assess frailty.