Tilburg frailty indicator. German translation and psychometric testing

The Tilburg frailty indicator (TFI) is a self-report measurement instrument which integrates the physical, psychological and social domains to assess frailty in older adults. The aim of this study was the adaptation of the TFI to a German version and testing of the psychometric properties.

This study surveyed 210 individuals aged 64-91 years living at home. The mean age of participants was M = 75.3±5.7 years with 62 % females. The internal consistency was tested with Cronbach's alpha. The test-retest reliability was calculated after 20 weeks. The German TFI was validated using alternative measures for assessment of the quality of life, e.g. Eurohis-QoL-8 and short form health survey (SF-12), the patient health questionnaire (PHQ), the geriatric anxiety inventory short form (GAI-SF), the social support scale (F-Soz-U-K-14) and the resilience scale (RS-11).

The internal consistency was acceptable with a value for Cronbach's alpha of 0.67. The test-retest reliability was good after 5 months α = 0.87 (physical domain r = 0.85, psychological domain r = 0.75 and social domain r = 0.84). The inter-item correlations ranged between - 0.06 and 0.57. Correlations with alternative frailty measures showed good convergent and divergent validity.

This study showed acceptable psychometric properties of the German adaptation of the TFI which was found to be age and frailty sensitive. The results of the validity of the TFI support the three domains integrated in the frailty score. Further application and testing of the German TFI in primary care and clinical settings are suggested to consolidate the findings.