The relationship of the geriatric nutritional risk index to mortality and length of stay in elderly patients with acute respiratory failure: A retrospective cohort study.

Background: Elderly people with acute respiratory failure (ARF) have prolonged length of hospital stay (LOS) and high mortality rates. Malnutrition is negatively correlated with these LOS and mortality. However, no tools have been used to detect the risk of malnutrition and assist in designing nutritional support for these patients. The geriatric nutritional risk index (GNRI) is reported as a novel tool for evaluating the risk of malnutrition. The aim of this study is to explore the relationship of the GNRI score with mortality and LOS in elderly patients with ARF.

Methods: Data of elderly patients diagnosed with ARF were retrieved from the Medical Information Mart for Intensive Care III (MIMIC-III) database. A total of 1250 patients were divided into two groups based on their GNRI score: the malnutrition risk group (GNRI ≤ 98) and no risk group (GNRI > 98). The primary endpoints of this study were hospital mortality and hospital LOS.

Results: The higher GNRI score was associated with lower hospital mortality and shorter hospital LOS. Odds ratio (OR) for hospital mortality of patients with nutritional risk (GNRI ≤ 98) was 1.264 (95% CI:1.067-1.497) in the adjusted model. Patients with GNRI ≤98 had longer hospital LOS (adjusted OR: 1.142, 95%CI: 1.044-1.250) compared with those with GNRI > 98. Subgroup analysis showed that higher GNRI was only significantly associated with lower hospital mortality in the patients that did not undergo mechanical ventilator (MV) treatment (adjusted OR: 0.985, 95% CI: 0.977-0.992, P < 0.01). Kaplan-Meier curve analysis showed that the 90-day survival was significantly lower in the group with nutrition risk (GNRI≤98) compared with the no risk group (GNRI > 98, p < 0.05).

Conclusion: These findings imply that GNRI is a useful prognostic tool in elderly patients with ARF.