title: Tilburg frailty indicator. German translation and psychometric testing.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department Health & Prevention, Ernst-Moritz-Arndt-University Greifswald, Robert-Blum-Str. 13, 17487, Greifswald, Germany. simone.freitag@uni-greifswald.de.
authors.forename: S
authors.initials: S
authors.lastname: Freitag
authors.affiliation: Department Health & Prevention, Ernst-Moritz-Arndt-University Greifswald, Robert-Blum-Str. 13, 17487, Greifswald, Germany. silke.schmidt@uni-greifswald.de.
authors.forename: S
authors.initials: S
authors.lastname: Schmidt
authors.affiliation: Faculty of Health, Sports and Social Work, Inholland University of Applied Sciences, Amsterdam, The Netherlands. robbert.gobbens@inholland.nl.
authors.forename: R J J
authors.initials: RJ
authors.lastname: Gobbens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D005260:Female; D016330:Frail Elderly / Q000523:psychology*; D015577:Geriatric Assessment / Q000379:methods*; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis*; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D057566:Self Report / Q000592:standards*; D012680:Sensitivity and Specificity; D014175:Translating
keywords: German translation; Psychometric properties; Reliability; Tilburg frailty indicator; Validity