Validation of the GLIM Malnutrition Criteria in Patients With Gastric Cancer at the Time of Diagnosis.

Gastric cancer is a major global public health challenge, with high incidence and mortality rates, particularly in Costa Rica. Like most oncological diseases, it significantly wastes nutritional status, often leading to malnutrition, which in turn worsens prognosis and survival. Early identification of malnutrition is therefore critical. The Global Leadership Initiative on Malnutrition (GLIM) has proposed standardized diagnostic criteria to systematically diagnose malnutrition across diverse clinical settings. However, validation has not been performed versus reference methods in many conditions, such as gastric cancer, although it is essential before widespread adoption. This study is aimed at validating the GLIM criteria for the timely detection of malnutrition in patients newly diagnosed with gastric cancer. We conducted a cross-sectional analysis in which GLIM-based assessments were compared against the Patient-Generated Subjective Global Assessment (PG-SGA) as the gold standard. Diagnostic performance was evaluated through sensitivity, specificity, and positive and negative predictive values; agreement was assessed with kappa statistics. Survival probability was further examined using Kaplan-Meier curves to estimate the prognostic relevance of nutritional status. A total of 72 patients were included. GLIM criteria demonstrated a sensitivity of 81.9% and specificity of 81.8% compared with PG-SGA, with moderate agreement (kappa = 0.48). Survival analysis revealed that both GLIM and PG-SGA consistently identified better outcomes among patients with preserved nutritional status. In conclusion, the GLIM criteria represent a valid and practical tool for the early detection of malnutrition in gastric cancer patients at diagnosis, supporting their integration into routine clinical practice to improve patient management and survival outcomes.