Validation of a dietary intake questionnaire through nutritional markers and clinical outcomes in patients with gastric cancer following gastrectomy.

This study aimed to validate a semiquantitative, patient-reported dietary questionnaire by assessing its correlation with nutritional screening tools and clinical outcomes over time. In this prospective study, a simplified questionnaire was developed to assess patients' diet volume (DV) intake relative to their preoperative baseline, along with meal and snack frequency. The questionnaire was administered preoperatively and at 1, 2, 3, 6, and 12 months after surgery. At each timepoint, a clinical nutritionist provided dietary counseling, and caloric intake per meal was evaluated. Nutritional assessments included body weight, laboratory markers, body composition (bioelectrical impedance spectroscopy), and nutritional screening tools (nutritional risk screening [NRS]-2002 and patient-generated subjective global assessment [PG-SGA]). Correlation analyses were performed between DV and nutritional parameters. Among the 341 patients, DV significantly decreased to 39.7% at 1 month and recovered to 74.8% by 12 months after surgery (P < .001). Snack frequency increased significantly at all postoperative timepoints, whereas meal frequency showed a transient increase only at 1 month. The estimated caloric intake initially decreased but then normalized by the 6th month. The NRS and PG-SGA scores peaked at 1 month and improved over time. DV was positively correlated with estimated caloric intake (r = 0.299-0.599, P < .05) and negatively correlated with weight loss (r = -0.119 to-0.301, P < .05). The strongest negative correlations were observed at 3 months, with NRS (r = -0.28) and PG-SGA (r = -0.46) scores. No significant correlations were found with white blood cell count or hemoglobin levels. The dietary questionnaire demonstrated a strong correlation with nutritional indicators and validated screening tools, supporting its potential utility in identifying nutritional risk, tracking recovery, and guiding interventions in postoperative patients with gastric cancer.