Predicting Mortality Based on Body Composition Analysis

Abstract

The role of the Nae/Ke ratio (the ratio of exchangeable sodium to exchangeable potassium) was examined as a nutritional marker in surgical patients in relation to anthropometrical and biochemical indexes by its ability to identify patients at risk for mortality after hospitalization. In 73 patients with sepsis and malnutrition (Training Group, Madrid) the following were determined: percentage of recent weight loss, triceps skin fold, midarm muscle circumference, serum albumin, serum transferrin, delayed hypersensitivity skin test response, total lymphocytes, and Nae/Ke ratio by multiple isotope dilution. The predictive power of Nae/Ke ratio was so strong (F = 105.1; p less than 0.00001) that it displaced anthropometric, biochemical, and immunologic variables from the linear equation derived from stepwise discriminant analysis using hospital mortality as the dependent variable. A theoretical curve of expected deaths was developed, based on an equation obtained by logistic regression analysis: Pr/death/ = 1/(1 + e[11.8-5.2 Nae/Ke]). Pre- and post-test probabilities on that curve allowed us to determine two cut-off values, Nae/Ke ratios of 1.5 and 2.5, which were markers for nonrisk and mortality, respectively. The model was tested in a heterogeneous data base of surgical patients (n = 417) in another hospital (Validation Group, Montreal). For patients exhibiting an abnormal Nae/Ke ratio (greater than 1.2) and a greater than 10% of probability of death, 54 deaths were expected and 53 observed (X2 = 1.8 NS). Two tests confirmed the basic agreement between the model and its performance, a G statistic of -0.704 and the area beneath the "receiver-operating-characteristic" (ROC) curve (Az = 0.904 + 0.0516 for the Madrid group vs. Az = 0.915 + 0.0349 for the Montreal group, NS). It was concluded from this analysis that, compared with the usual anthropometric measurements, the Nae/Ke ratio, if available, is the best method for identifying malnourished patients at risk of dying.

Sarcopenia and its implications for the elderly

“…Therefore, it is no wonder that elderly, sarcopenic patients fare worse than young, healthy adults for almost all diseases. Tellado et al (1989) have shown that measurement of body cell mass was the only independent determinant of survival in intensive care unit patients in multivariate analysis, removing the signi®-cance of univariate predictors such as albumin, age, and even diagnosis. Thus, the metabolic signi®cance of sarcopenia in illness should be considered independently of its functional impact during times of better health, as both are important to the survival and well-being of elderly persons.…”

“…The available data, based on starvation (Winick, 1979), AIDS patients (Kotler et al, 1989), and critical illness (Tellado et al, 1989), suggest that loss of more than about 40% of baseline lean mass is fatal. Baseline' is a slippery concept here, because again absolute mass is not explanatory Ð basketball players do not necessarily outlive jockeys Ð but rather the amount of loss as a function of the baseline mass that the individual started with.…”

Utility of Standard Nutritional Parameters in Detecting Body Cell Mass Depletion in Patients With End-Stage Liver Disease

“…1 The clinical significance of BCM depletion has been shown in a number of clinical settings, including HIV infection and critical illness. 16,17 Furthermore, significant loss of BCM before liver transplantation has been associated with a greater than 3-fold increase in posttransplantation mortality. 9,18 Although measurement of BCM provides clinically relevant information about the nutritional status of patients with end-stage liver disease, its utility as a nutritional parameter has been limited by the expense and technical difficulty associated with its determination.…”

Interleukin 1 receptor blockade attenuates the host inflammatory response.

“…Although the consequences of injury can result in increased morbidity (2)(3)(4), the mechanisms underlying these changes in host physiology remain poorly defined. Several cytokines, including interleukin 1 (IL-1), tumor necrosis factor a (TNFa), and interleukin 6 (IL-6), are mediators of the host response to inflammation (5)(6)(7)(8)(9)(10).…”