Cross-cultural adaptation and psychometric validation of the physical oral health index in Chinese older inpatients.

PURPOSE: Oral health is a key component of healthy aging. According to the dual-axis conceptual model, oral health consists of a physical axis and a psychosocial axis. While the psychosocial axis is well covered by validated patient-reported instruments with established Chinese versions, no comprehensive, theoretically grounded instrument for assessing the physical dimension of oral health is currently available in China. The Physical Oral Health Index (PHOX), grounded in a dual-axis theoretical model, is a comprehensive instrument specifically designed to assess the physical dimension of oral health, including teeth, soft tissues, jaw function, and pain perception. Therefore, this study aimed to develop a Chinese version of the PHOX and evaluate its psychometric properties among older inpatients in China. PATIENTS AND METHODS: The PHOX was cross-culturally adapted using Cruchinho's eight-step methodology. A total of 1,365 older inpatients (aged ≥ 65 years) from five departments of a tertiary hospital in Zhejiang Province, China, were enrolled. The psychometric properties of the Chinese version were evaluated in terms of content validity, construct validity, internal consistency, and test-retest reliability. RESULTS: The Chinese version retained the original 14-item, five-factor structure. Following revision, both the item-level content validity index and the scale-level content validity index reached 1.00. The scale demonstrated excellent internal consistency (Cronbach's α = 0.905; CR = 0.898-0.930) and test-retest reliability (ICCtotal = 0.923; ICCdimension = 0.858-0.919). Exploratory factor analysis supported a five-factor structure, explaining 79.2% of the total variance, with factor loadings ranging from 0.71 to 0.95. Confirmatory factor analysis conducted using the calibration, validation, and total samples demonstrated a robust model fit (RMSEA = 0.065, CFI = 0.975, and SRMR = 0.027). Convergent properties (AVE = 0.742-0.834) and discriminant validities were confirmed. Weight equivalence analysis further supported the applicability of the original scoring weights in the Chinese population. CONCLUSION: The PHOX-Chinese demonstrated strong psychometric properties and good cultural adaptability, supporting its use as a comprehensive tool for assessing physical oral health among older inpatients. Its application in clinical practice and research may facilitate the early identification of oral health impairments, inform individualized oral care planning, and support targeted nursing interventions that may contribute to improved health outcomes in aging populations.