Association between the geriatric nutritional risk index and adverse post-extubation outcomes for critically ill older adults: a retrospective study

Background and purpose Malnutrition commonly predicts adverse outcomes among older adults in the intensive care unit (ICU). The Geriatric Nutritional Risk Index (GNRI) is a simple and practical tool for assessing nutritional status in older adults. This study aims to explore the association between GNRI and adverse post-extubation outcomes in critically ill older adults. Methods A total of 1,153 older adults aged 65-82 years in the ICU were included in this retrospective cohort study. GNRI categories were stratified into four subgroups based on nutritional risk: major risk (GNRI < 82), moderate risk (GNRI 82-91), low risk (GNRI 92-98), and no risk (GNRI > 98). Adverse post-extubation outcomes included mortality or pneumonia within 30 days post-extubation, reintubation within 72 h, post-extubation dysphagia, and length of stay (LOS) in the ICU and hospital. Multivariable logistic regression analysis and restricted cubic spline (RCS) were used to explore the association between GNRI categories and dichotomous adverse outcomes. Additionally, multivariable linear regression was used to evaluate the association between GNRI and LOS in the ICU and hospital. Results Older adults with dichotomous adverse outcomes had lower GNRI values compared with those without (P-value<0.001), and increasing LOS in ICU and hospital was associated with decreasing GNRI value (P for trend<0.001). Patients at major nutritional risk had the highest risk of mortality [OR = 2.76, 95%CI: 1.40 similar to 5.46] or pneumonia [OR = 3.07, 95%CI: 1.42 similar to 6.68] within 30 days post-extubation, reintubation within 72 h [OR = 2.41, 95%CI: 1.06 similar to 5.49] and post-extubation dysphagia [OR = 2.94, 95%CI: 1.19 similar to 7.31](P for trend<0.001). The RCS study also validated the linear relationship between GNRI and mortality/pneumonia within 30 days post-extubation and post-extubation dysphagia. Conversely, there were non-linear associations between GNRI and ICU and hospital LOS, as well as reintubation within 72 h. Furthermore, GNRI showed a significant negative correlation with LOS in both the ICU and hospital. Kaplan-Meier curve analysis demonstrated that survival within 30 days post-extubation was significantly reduced in major nutritional risk group compared to the no risk group (P-value = 0.018). Conclusions Our findings demonstrated that major nutritional risk defined by GNRI was associated with a higher risk of adverse post-extubation outcomes in critically ill older adults.