Cultural Adaptation and Validation of the Oral Frailty Index-8 for Turkish Older Adults

Oral frailty, a multidimensional decline in oral function involving chewing, swallowing, and oral behaviours, is a recognised precursor of dysphagia, malnutrition, and physical frailty. The Oral Frailty Index-8 (OFI-8) is a brief self-report screening tool for assessing oral frailty. This study's aim is to adapt the OFI-8 into Turkish (OFI-8-TR) and evaluate its psychometric properties among older adults.

A cross-sectional study was conducted in 341 adults aged ≥ 65 years attending a geriatrics outpatient clinic. Internal consistency (KR-20), test-retest reliability (ICC), and construct validity (convergent, known-groups, and confirmatory factor analyses) were evaluated. Comparator measures included the FRAIL (Fatigue, Resistance, Ambulation, Illnesses, and Loss of weight) scale, Clinical Frailty Scale (CFS), Eating Assessment Tool-10 (EAT-10), Functional Oral Intake Scale (FOIS), and Mini Nutritional Assessment-Short Form (MNA-SF).

The OFI-8-TR showed acceptable internal consistency (KR-20 = 0.62) and excellent test-retest reliability (ICC = 0.898). Confirmatory factor analysis supported a one-factor model (Comparative Fit Index (CFI) = 0.93, Goodness-of-Fit Index (GFI) = 0.95, adjusted Goodness-of-Fit Index (AGFI) = 0.91). Convergent validity was confirmed through strong correlations with the EAT-10 (r = 0.63) and FOIS (r = -0.62), and moderate correlations with FRAIL, CFS, and MNA-SF in the expected directions. Known-groups validity showed significantly higher scores among participants with malnutrition or risk of malnutrition.

The OFI-8-TR is a valid and reliable instrument for assessing oral frailty and identifying swallowing-related and nutritional vulnerability in older adults. Its brevity and multidimensional structure make it a practical screening tool for routine geriatric assessments to support early identification of swallowing- and nutrition-related vulnerability.