Factorial Validity and Reliability of the Chemotherapy Dietary  Adherence Scale: A Tool for Nutritional Assessment in Cancer Care

Hari Prakash G; Sunil Kumar D; Kiran PK; Vanishri Arun; Deepika Yadav; Shwethashree M; Arun Gopi; Praveen Kulkarni

doi:10.31557/apjcc.2025.10.4.1101-1108

Authors

Hari Prakash G Assistant Professor, Division of Public Health, Department of Allied Health Sciences, Ramaiah University of Applied Sciences, Bengaluru, India.
Sunil Kumar D Professor and Head, Department of Community Medicine, JSS Medical College, JSS Academy of Higher Education and Research, Mysuru, India.
Kiran PK Assistant Professor, Department of Medical Oncology, JSS Medical College, JSS Academy of Higher Education and Research, Mysuru, India.
Vanishri Arun Associate Professor, Department of Information Science and Engineering, SJCE, JSS STU, Mysuru, India.
Deepika Yadav Research Scientist-II (Medical), ICMR National Institute for Implementation Research on Non-Communicable Diseases, Jodhpur, India.
Shwethashree M Associate Professor, Department of Community Medicine, JSS Medical College, JSS Academy of Higher Education and Research, Mysuru, India.
Arun Gopi Assistant Professor, Department of Community Medicine, JSS Medical College, JSS Academy of Higher Education and Research, Mysuru, India.
Praveen Kulkarni Professor, Department of Community Medicine, JSS Medical College, JSS Academy of Higher Education and Research, Mysuru, India.

DOI:

https://doi.org/10.31557/apjcc.2025.10.4.1101-1108

Keywords:

Dietary adherence, Chemotherapy, Psychometric validation, Factor analysis, Nutritional adherence, CDAS, Cancer nutrition

Abstract

Background: Nutritional adherence is vital in improving clinical outcomes for chemotherapy patients. The lack of validated tools to assess dietary adherence during chemotherapy prompted the development and psychometric validation of the Chemotherapy Dietary Adherence Scale (CDAS).

Objective: To develop, refine, and validate the CDAS, assessing its reliability and factorial structure through exploratory and confirmatory factor analyses.

Methods: This two-phase, cross-sectional study was conducted in the Department of Medical Oncology at a tertiary care cancer centre. Data were collected from 245 chemotherapy patients over a period of two months. Phase 1 involved exploratory factor analysis (EFA) on an initial scale, followed by refinement to address weak inter-item correlations. Phase 2 validated the revised scale using confirmatory factor analysis (CFA). Reliability was assessed using Cronbach’s alpha, and statistical analysis was conducted using SPSS version 26 and Python’s semopy library.

Results: The study population had a mean age of 58.13 years (SD, 9.85) and consisted predominantly of skilled workers (67.1%). The 7-item CDAS demonstrated excellent internal consistency (Cronbach’s alpha = 0.83), with subscales showing strong reliability: Nutritional Adherence (α = 0.79) and Dietary Adjustment (α = 0.81). EFA revealed a two-factor structure explaining 70.5% of the total variance. CFA confirmed this structure with exceptional model fit (χ² = 12.09, df = 13, p = 0.52; CFI = 1.00; GFI = 0.98; TLI = 1.00; RMSEA = 0.00). All items showed significant factor loadings (p < 0.001), with values ranging from 1.058 to 1.262. The moderate correlation between factors (r = 0.168, p < 0.001) indicated that they represented distinct but related dimensions of dietary adherence.

Conclusions: The CDAS demonstrated robust psychometric properties, with a clear two-factor structure that captures distinct aspects of dietary adherence among chemotherapy patients. The validated scale provides a reliable and valid tool for assessing nutritional adherence and dietary adaptations during chemotherapy, potentially enhancing clinical assessment and targeted nutritional interventions.