Cachexia Index and CRP–Triglyceride–Glucose Index as Prognostic Predictors in Cancer Hospitalized Patients

Background/Objectives: Cancer cachexia is linked to poor oncological outcomes. The Cachexia Index (CXI) and the CRP–triglyceride–glucose index (CTI), composite markers of body composition, nutrition, and inflammation, have emerged as prognostic tools, but their value in hospitalized cancer patients remains unexplored. We evaluated their association with short- and long-term outcomes in this population. Methods: This retrospective, observational study included 139 hospitalized patients with active cancer by a Nutrition Unit during 2023. Nutritional status was assessed using the Global Leadership Initiative on Malnutrition (GLIM) criteria; body composition was quantified by computed tomography (CT) imaging at L3 level. Primary outcomes were in-hospital mortality, intensive care unit (ICU) admission due to clinical deterioration, hospital readmission, and overall survival. Each index was analyzed as a continuous variable, in quartiles, by the median, and at an exploratory ROC-derived cut-off, using logistic and Cox regression. Results: CXI at its ROC-derived cut-off (<9.03; AUC 0.69) was associated with in-hospital mortality (OR 3.91; 95% CI 1.22–12.52; p = 0.022) and overall survival (HR 1.75; 95% CI 1.04–2.95; p = 0.035), unlike its continuous, quartile, and median forms. CTI at its cut-off (≥6.71; AUC 0.704) remained associated with ICU admission after adjustment for surgery and age (OR 5.52; 95% CI 1.64–18.54; p = 0.006) or surgery and myosteatosis (OR 4.94; 95% CI 1.48–16.47; p = 0.009), but not with survival. Conclusions: CXI and CTI show complementary, threshold-dependent prognostic value: CXI identifies in-hospital and long-term mortality risk, and CTI, more consistently than CXI, identifies ICU admission risk due to clinical deterioration. These exploratory findings need prospective, multicenter validation.