Deepening the understanding of the structural validity of the Tilburg Frailty Indicator.

BACKGROUND: Psychometric properties of the Tilburg Frailty Indicator (TFI) have shown low internal consistency for psychological and social domains, and evidence for its structure validity is controversial. Moreover, research on TFI is frequently limited to community dwellings. AIMS: To evaluate structural validity, reliability, and convergent and divergent validity of the Spanish version of the Tilburg Frailty Indicator (TFI) in both community-dwelling and institutionalized older people. MATERIALS AND METHODS: A cross-sectional study was conducted on Spanish older adults (n = 457) recruited from both community settings (n = 322) and nursing homes (n = 135). Participants completed the TFI and other frailty instruments: Fried's Frailty Phenotype, Edmonton Frailty Scale, FRAIL Scale, and Kihon Checklist (KCL). Confirmatory Factor Analysis (CFA), and reliability and validity coefficients were estimated. RESULTS AND DISCUSSION: Some items from physical and social domains showed low factor loadings (< 0.40). The three-factor CFA model showed better fit indices after depurating these items. Reliability estimates were good (CRI ≥ 0.70) for physical and psychological domains in the institutionalized sample, while in the community dwellings, only physical domain reliability was adequate. Convergent and divergent validity of physical and psychological domains was good, except for some alternative psychological measures highly correlating with the TFI physical component (KCL-depressive mood and Edmonton mood). However, the social domain showed low correlations with some social indicators. CONCLUSION: The findings of this study clarify some of the controversial validation results of the TFI structure and provide evidence to improve its use in psychometric terms. CLINICAL TRIAL REGISTRATION NUMBER: NCT03832608.