Development and Validation of a Disease-Specific Instrument to Measure Diet-Targeted Quality of Life for Postoperative Patients with Esophagogastric Cancer.

ABSTRACT

BACKGROUND: Patients who have undergone esophagectomy or gastrectomy have certain dietary limitations because of changes to the alimentary tract. This study attempted to develop a psychometric scale, named "Esophago-Gastric surgery and Quality of Dietary life (EGQ-D)," for assessment of impact of upper gastrointestinal surgery on diet-targeted quality of life. METHODS: Using qualitative methods, the study team interviewed both patients and surgeons involved in esophagogastric cancer surgery, and we prepared an item pool and a draft scale. To evaluate the scale's psychometric reliability and validity, a survey involving a large number of patients was conducted. Items for the final scale were selected by factor analysis and item response theory. Cronbach's alpha was used for assessment of reliability, and correlations with the short form (SF)-12, esophagus and stomach surgery symptom scale (ES(4)), and nutritional indicators were analyzed to assess the criterion-related validity. RESULTS: Through multifaceted discussion and the pilot study, a draft questionnaire comprising 14 items was prepared, and a total of 316 patients were enrolled. On the basis of factor analysis and item response theory, six items were excluded, and the remaining eight items demonstrated strong unidimensionality for the final scale. Cronbach's alpha was 0.895. There were significant associations with all the subscale scores for SF-12, ES(4), and nutritional indicators. CONCLUSIONS: The EGQ-D scale has good contents and psychometric validity and can be used to evaluate disease-specific instrument to measure diet-targeted quality of life for postoperative patients with esophagogastric cancer.