Comparative Prognostic Accuracy of Objective Nutritional Indices in Critically Ill Patients with Sepsis: A Systematic Review and Meta-Analysis

Background: Nutritional indices are increasingly studied as prognostic tools in sepsis, but their comparative value remains uncertain. We conducted a systematic review and meta-analysis to evaluate associations between major nutritional indices and mortality in adult sepsis. Methods: PubMed, Embase, and Web of Science were searched for eligible studies. Pooled odds ratios (ORs), hazard ratios (HRs), and diagnostic accuracy measures were synthesized using random-effects models. Subgroup and sensitivity analyses explored heterogeneity and tested robustness. Results: Twenty-two studies comprising 51,769 patients were included. Higher modified Nutrition Risk in the Critically Ill (mNUTRIC) and Nutrition Risk in the Critically Ill (NUTRIC) scores were associated with increased mortality (OR 3.10, 95% CI 1.39–6.89; OR 4.54, 95% CI 2.13–9.66, respectively). In contrast, a higher Prognostic Nutritional Index (PNI) was consistently associated with lower mortality (OR 0.64, 95% CI 0.50–0.83; HR 0.66, 95% CI 0.54–0.81), and a higher Geriatric Nutritional Risk Index (GNRI) was associated with improved survival (HR 0.66, 95% CI 0.44–0.98). Controlling Nutritional Status (CONUT) showed a non-significant trend toward higher mortality (OR 1.83, 95% CI 0.94–3.54). In diagnostic analyses, mNUTRIC demonstrated better discrimination than PNI (AUC 0.84 vs. 0.74). Heterogeneity in mNUTRIC analyses decreased markedly after stratification by mortality endpoint. Conclusions: Nutritional indices are prognostically informative in sepsis, but performance is context-dependent. mNUTRIC/NUTRIC show stronger short-term signals in ICU cohorts, likely reflecting illness-severity components, and cross-index comparisons remain indirect due to heterogeneous thresholds and endpoints.