No incremental discriminative value of hemoglobin beyond GNRI for predicting mortality in older adult with sepsis

BACKGROUND: The prognostic value of hemoglobin-combined Geriatric Nutritional Risk Index (H-GNRI) in older adult septic patients remain unexplored. This study aimed to investigate the association between H-GNRI and both short-term and long-term mortality in older adult patients with sepsis. METHODS: This retrospective cohort study analyzed older adult with sepsis from the MIMIC-IV database. Patients aged ≥ 65 years meeting sepsis-3 criteria were included, excluding those with chronic kidney disease or severe liver disease. The H-GNRI scoring system was developed by combining optimal cutoff values for GNRI and hemoglobin determined through X-tile analysis. Propensity score matching (1:1) was performed to minimize confounding. The primary outcome was 28-day mortality. Cox proportional hazards models and ROC analysis were used to evaluate prognostic performance and discriminatory ability. RESULTS: The 28-day mortality rates increased significantly across risk groups (45.0%, 61.7%, and 72.5% for low, intermediate, and high-risk groups, respectively; P < 0.001). This trend persisted for 180-day and 1-year mortality. After adjusting for confounders, higher-risk H-GNRI groups remained independently associated with increased mortality risk. However, H-GNRI demonstrated poor discriminatory performance with an AUC of 0.58 for 28-day mortality prediction. CONCLUSION: While H-GNRI demonstrated significant associations with mortality in older adult sepsis patients, it exhibited poor discriminatory performance, limiting its utility as a standalone risk prediction tool. Further studies are needed to develop more sophisticated nutritional risk stratification approaches for critically ill patients.