Nutrition-associated health levels in persons with cancer: item response modelling based on the International Classification of Functioning, Disability and Health.

BACKGROUND: The nutritional status of individuals with cancer is a crucial determinant of their health and well-being, and addressing nutrition-related functioning conditions is essential for maintaining physical activity levels and participating in daily activities. AIM: This study aims to identify an evidence-based International Classification of Functioning, Disability and Health (ICF) scale using item response theory for nutrition conditions in patients with cancer, which can differentiate and assess nutrition-related functioning conditions of cancer survivors. DESIGN: Cross-sectional study. SETTING: Sir Run Run Hospital, Nanjing Medical University. POPULATION: One hundred cancer patients were enrolled. METHODS: Via convenience sampling, the study administered a questionnaire consisting of 89 ICF items to participants. The original five-point rating system was binarized (1 = no problem, 0 = problem). Through data shaping, non-parametric IRT analysis and parametric IRT analysis, psychometric properties of nutritional ICF scale were calculated using R software. RESULTS: The study extracted a unidimensional scale with 32 items and constructed 2-parameter logistic model with good fitness, whose root mean square error approximation (RMSEA) = 0.0759, Tucker-Lewis Index (TLI) = 0.9655, and Comparative Fit Index (CFI) = 0.9677. The model demonstrated high reliability, as indicated by a Cronbach's α of 0.95, Guttman λ2 of 0.95, Molenaar Sijtsma statistic of 0.96 and a latent class reliability coefficient (LCRC) of 0.98. Besides, there was a strong correlation between the total score of 32 ICF items and the score of Patient-Generated Subjective Global Assessment (PG-SGA, P<0.001, r=-0.77) and Mini Nutritional Assessment (MNA, P<0.001, r=0.76), suggesting the 32-item scale had high validity. CONCLUSIONS: The study constructed an evidence-based ICF scale for nutrition conditions in patients with cancer with 32-item and 2PLM for evaluating nutrition-associated health level in persons with cancer, including high validity and reliability. CLINICAL REHABILITATION IMPACT: The IRT model based on ICF provided a promising assessment tool to discriminate nutrition-associated health level of persons with cancer, and offered an auxiliary method for selecting rehabilitation intervention targets. This has the potential to lead to improved outcomes in cancer treatment and increased quality of life for cancer survivors.