Vector bioimpedance detects situations of malnutrition not identified by the indicators commonly used in geriatric nutritional assessment: A pilot study.

OBJECTIVE: To compare body composition as assessed by conventional and vector bioelectrical impedance analysis according to the nutritional cataloging using body mass index (BMI) in a group of institutionalized elderly.

METHODS: Cross-sectional study in 38 institutionalized elderly. Body composition was estimated by bioimpedance analysis. Differences in body composition were analyzed using t-test and ANOVA, or their corresponding nonparametric tests. Statistical significance was set at p<0.05.

RESULTS: Based on BMI, the sample showed overweight (average BMI: 26.4kg/m2 ), and women had higher BMI values than men (28.9 vs. 25.5kg/m2 ). Based on waist circumference, abdominal obesity was detected in 60.7% of men and 80% of women. Conventional bioimpedance analysis (BIA) yielded high fat mass values and slightly depleted skeletal muscle mass, compatible with sarcopenic obesity. All individual impedance vectors were located on the right of the major axis of the tolerance ellipses, reflecting body-cell-mass depletion in all subjects, regardless of BMI cataloging.

CONCLUSIONS: Bioelectrical impedance vector analysis (BIVA) detects body compartment changes in institutionalized elderly that are not identified by the most widely used clinical practice nutritional indicators, such as BMI, waist circumference, and BIA-estimated body composition.