The usefulness of the updated bioelectrical impedance vector analysis references for assessing malnutrition, sarcopenia and predicting mortality in hospitalized patients

The application of validated pre-screening tools is crucial in clinical practice to identify patients at risk for disease. Bioelectrical Impedance Vector Analysis (BIVA) has gained recognition as a qualitative method for monitoring body composition and assessing the health status of hospitalized patients. This study investigates the utility of updated BIVA reference standards in evaluating malnutrition, sarcopenia, and mortality among hospitalized individuals.

This retrospective observational study included 2.872 patients admitted to Quironsalud Málaga Hospital between January 2019 and January 2024. Malnutrition and sarcopenia were diagnosed using the Global Leadership Initiative on Malnutrition (GLIM) and the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) guidelines. Mortality was defined as death within one year of their initial discharge or later admissions. BIVA was performed using the former and the new 50th, 75th, and 95th reference tolerance ellipses of general population.

BIVA revealed significant differences in bioimpedance vectors between malnourished (n = 1187, 544 women) and non-malnourished patients, sarcopenic (n = 136, 51 women) and non-sarcopenic patients, and non-survivors (n = 317, 160 women) compared to survivors. When previous BIVA references (Piccoli 1995) were applied, the bioimpedance vectors for malnourished, sarcopenic, and non-surviving patients fell within the 75th tolerance ellipses. However, with updated references, these vectors shifted rightward, moving outside the 75th and 95th tolerance ellipses. Univariate Cox analysis showed that participants with vectors outside the new 95th tolerance ellipses faced significantly higher mortality risk (HR = 6.22 [95 % CI 4.40-8.80], p < 0.001) and lower survival rates (log-rank test p < 0.001) compared to those within the 75th ellipses. These trends persisted even after adjusting for age, sex, and BMI (HR = 4.79 [95 % CI 3.29-6.97], p < 0.001). The new reference ellipses demonstrated greater prognostic accuracy compared to the older ones, emphasizing their value in identifying high-risk patients.

The implementation of BIVA with newly established reference tolerance ellipses significantly enhances the evaluation of body composition and overall health in hospitalized patients. These updated tolerance ellipses are instrumental in accurately identifying malnutrition, sarcopenia, and heightened mortality risks. The delineation of specific mortality risk zones underscores the potential of incorporating these advanced BIVA ellipses into routine pre-screening protocols, thereby optimizing clinical nutritional assessments and interventions.