Development and preliminary validation of the Dietary Self-management Behavior Questionnaire (DSMBQ) for breast cancer patients during chemotherapy: three rounds of survey.

Background: Adverse effects during chemotherapy severely impact the daily diet of breast cancer (BC) patients. Engaging in dietary self-management is crucial for healthy lifestyle and recovery. This study aims to create the Dietary Self-management Behavior Questionnaire (DSMBQ) and preliminarily validate its reliability, validity, and discriminative ability for BC patients undergoing chemotherapy.

Methods: The questionnaire was developed through a scoping review, patient interviews, and referenced to previous scales. The initial draft item pool underwent two rounds of Delphi expert consultations, creating the draft DSMBQ with 6 predefined dimensions and 98 items. Subsequently, the draft questionnaire underwent three rounds of investigation. The results from the first two surveys were utilized for item selection, the third was to assess the construct of the final DSMBQ. Three groups (n = 158, 385, and 771) were conveniently sampled from three hospitals in Xi'an and Zhengzhou cities. Lastly, 150, 378, and 760 participants, respectively, completed valid questionnaires. Exploratory factor analysis and variability analysis were used to assess the draft questionnaire, and the structure was further examined through confirmatory factor analysis.

Results: The final DSMBQ comprised 22 items organized into 4 dimensions. The cumulative variance contribution rate totaled 62.96%. The Cronbach's α demonstrated high internal consistency at 0.91, while the split-half reliability coefficient was 0.83, and the test-retest reliability coefficient reached 0.94. Correlation coefficients between the scores of each dimension and the total score ranged from 0.697 to 0.751. With the exception of the normed fit index (NFI) and the non-normed fit index (NNFI) at 0.89 (close to 0.90), all other indicators met statistical requirements. Patients exhibited varying average scores for each dimension of the DSMBQ based on differences in age, education level, Body Mass Index (BMI), menopausal status, and cancer stage (P < 0.05).

Conclusion: The DSMBQ demonstrated good reliability, validation, and discriminative ability in Chinese BC patients undergoing chemotherapy. Tailored to the cultural context, the DSMBQ emerges as a high-quality tool for the nuanced assessment of dietary self-management in BC patients by focusing on lifestyle behavior changes. It holds the potential to enhance subjective initiative and confidence, facilitating increased patient participation in their healthcare.