Why GNRI matters for the elderly with bloodstream infections
Bloodstream infections (BSIs) place a heavy burden on hospitalized patients, and the impact is often worse in older adults. Malnutrition is a common comorbidity in the elderly and can worsen infection outcomes by impairing immune function and healing. The Geriatric Nutritional Risk Index (GNRI) is a simple, clinically accessible tool that uses albumin, height, and weight to gauge nutrition-related risk in older patients. While GNRI has shown prognostic value in general geriatric populations, its role in predicting outcomes for patients with BSIs needed clarification.
Study design and methods
This two-year retrospective study analyzed elderly inpatients with healthcare-associated BSIs admitted to a large Chinese tertiary hospital from January 2020 to December 2021. A total of 464 patients aged 60 years and older were included. GNRI was calculated at admission, and patients were categorized into four nutrition-risk groups: GNRI > 98 (no risk), 92–98 (low risk), 82–92 (moderate risk), and <82 (major risk). The primary outcome was in-hospital mortality. Descriptive analyses characterized GNRI groups, while logistic regression identified independent associations with mortality. A restricted cubic spline (RCS) examined nonlinear relationships between GNRI and death, and a cross-validated case-control approach assessed model robustness.
Key variables collected included age, comorbidities, invasive device use, and routine laboratory parameters at admission, enabling adjustment for potential confounders in multivariate models.
Key findings
Among the 464 patients, 203 (43.8%) had GNRI in the no-risk category, 70 (15.1%) in the low-risk group, 118 (25.4%) in the moderate-risk group, and 73 (15.7%) in the major-risk group. In-hospital mortality rose with worsening GNRI status (P < 0.001). After adjusting for covariates, GNRI remained a strong, independent predictor of mortality: major-risk GNRI (<82) carried an odds ratio (OR) of 3.16 (95% CI: 1.52–6.58; P = 0.002), and moderate risk (82–<92) carried an OR of 1.91 (95% CI: 1.00–3.62; P = 0.049). Each unit increase in GNRI was protective (OR 0.96; 95% CI: 0.94–0.98; P = 0.001).
The nonlinear pattern revealed by the RCS analysis showed mortality risk declined as GNRI rose, with the curve plateauing around GNRI scores of 96–98. In other words, improving GNRI up to roughly 96–98 was associated with meaningful reductions in mortality risk in elderly BSI patients.
Clinical implications
These results position GNRI as a practical, independent prognostic tool for assessing nutrition-related risk in elderly patients with BSIs. Routine GNRI assessment at hospital admission can help clinicians identify high-risk individuals who may benefit from prompt, targeted nutritional interventions. While mild malnutrition (GNRI 92–98) showed limited impact on mortality in this cohort, moderate and major malnutrition were clearly linked to worse outcomes, underscoring the need for early nutritional support in vulnerable patients.
Beyond nutrition, the study highlighted associations between invasive devices (e.g., urinary catheters, central venous lines) and mortality, suggesting a need for careful device stewardship in this high-risk population.
Limitations and future directions
As a single-center, retrospective analysis, generalizability to broader populations warrants confirmation in multicenter studies. GNRI was measured only at admission, precluding evaluation of nutritional trajectory during hospitalization. Potential Neyman bias and residual confounding may influence effect estimates. Prospective, longitudinal research should explore GNRI changes over time and their relation to BSI outcomes, as well as the impact of structured nutritional interventions guided by GNRI risk stratification.
Conclusion
The study provides the first evidence that GNRI independently predicts in-hospital mortality among elderly patients with BSIs, with a nonlinear relationship indicating substantial risk reduction as GNRI improves toward normal ranges. Clinicians should consider early GNRI assessment and targeted nutrition support to potentially reduce BSI-related mortality in the aging population.
