Validity of the Turkish version of the Oral Frailty Index-8 and its relationship with frailty, malnutrition, and sarcopenia in older adults

Abstract

Background/aim: The Oral Frailty Index-8 (OFI-8) is a reliable screening for oral frailty. In our study, while presenting the Turkish reliability and validity study of the OFI-8, we also aimed to establish a cut-off value for oral frailty in Turkish population. Materials and methods: Patients who presented to the outpatient clinic between January 2024 and January 2025 were evaluated. The test’s internal consistency and test–retest reliability were assessed. Divergent validity was evaluated using frailty scores, muscle strength, and nutritional status. A receiver operating characteristic (ROC) curve was generated to determine the optimal cut-off values for identifying frailty, malnutrition, and probable sarcopenia. Oral frailty status was then analyzed in relation to demographic characteristics, comorbidities, and geriatric syndromes. Regression analyses were performed to adjust for confounding factors. Results: In 162 patients, internal consistency was quantified with a Cronbach’s α of 0.728, and test–retest reliability was quantified with an intraclass correlation coefficient (ICC) of 0.961. Construct validity was supported by exploratory factor analysis, and divergent validity was confirmed through significant correlations with frailty, muscle strength, and nutritional status. A cut-off score of >5 on the OFI-8 was identified for predicting physical frailty, malnutrition, and probable sarcopenia: for frailty status, the area under the curve (AUC) was 0.75 [95% confidence interval (CI) 0.67–0.82; p < 0.001], sensitivity 0.85 and specificity 0.56; for probable sarcopenia, AUC was 0.68 (95% CI 0.60–0.77; p < 0.001), sensitivity 0.71 and specificity 0.52; and for nutritional status, AUC was 0.76 (95% CI 0.68–0.84; p < 0.001), sensitivity 0.86 and specificity 0.55. Independent of confounding factors, probable sarcopenia, physical frailty, polypharmacy, malnutrition, and falls remained significantly associated with oral frailty (OFI-8 score ≥5). Conclusion: OFI-8 demonstrates good validity and reliability for detecting oral frailty in Turkish older adults, supporting early diagnosis and intervention to address better related conditions such as frailty, probable sarcopenia, and malnutrition.