Objective: To assess the body composition in a group of malnourished patients with anorexia nervosa as compared to healthy controls, before and after nutritional support, by means of anthropometry and bioimpedance.
Methods: Prospective observational study. Complete anthropometry was performed as well as bioimpedance analysis in 12 women (24.5 years) with restrictive anorexia nervosa at hospital admission and weekly thereafter during re-feeding. The control group was formed by 24 healthy women (21 years). The Student's t test, the Mann-Whitney U test, the Student's t test for repeated measurements, and the Wilcoxon's test were applied. The level of agreement between anthropometry and BIA was calculated by the interclass correlation coefficient and the Bland-Altman s test.
Results: The patients had significant improvements in all indexes of body composition throughout their hospital staying although their values at discharge still were lower than those of the control subjects. The average weight gain was 5.22 kg (SD: 1.42), of which 51.4% was fat mass, preferentially centrally distributed. In the control subjects, the BIA equation that correlated the best with anthropometrics was Sun s equation (CCI = 0.896); in the patients, the level of agreement was weaker, both at hospital admission and at hospital discharge.
Conclusions: Re-feeding produces weight gain, essentially at the expense of fat mass, which is centrally distributed; the nutritional status is not reestablished. The level of agreement between anthropometry and bioimpedance for studying body composition is acceptable, especially in healthy subjects. In those cases with severe changes in body composition and/or water balance, anthropometry is recommended when vectorial BIA or some other gold standard method are not available for the analysis of body composition.
Objetivo: Evaluar la composición corporal en un grupo de pacientes desnutridas con anorexia nerviosa, respecto de controles sanas, antes y después del soporte nutricional, mediante antropometría y bioimpedancia. Métodos: Estudio observacional prospectivo. Se realizó una antropometría completa y un análisis de bioimpedancia a 12 mujeres con anorexia nerviosa restrictiva (24,5 años) al ingreso hospitalario y semanalmente durante la realimentación. El grupo control estuvo formado por 24 mujeres sanas (21 años). Se aplicaron los test t-Student, U-Mann-Whitney, t-Student para medidas repetidas o Wilcoxon. La concordancia entre antropometría y BIA se analizó mediante el coeficiente de correlación intraclase y Bland-Altman. Resultados: Las pacientes mejoraron significativamente todos los índices de composición corporal a lo largo de la estancia hospitalaria, aunque sus valores al alta siguieron siendo menores que los de las controles. La media de peso ganado fue 5,22 kg (DE: 1,42), de los que el 51,4% fueron masa grasa, con distribución central preferentemente. En las controles la ecuación de BIA que mejor concuerda con antropometría es la de Sun (CCI = 0,896); en las pacientes la concordancia fue más débil, al ingreso y al alta. Conclusiones: La realimentación produce una ganancia ponderal, fundamentalmente a expensas de masa grasa, con distribución central; no se consigue restablecer el estado nutricional. La concordancia entre antropometría y bioimpedancia para el estudio de la composición corporal es aceptable, especialmente en sujetos sanos. Se recomienda emplear antropometría, si no se dispone de BIA vectorial o algún método gold estandard para el análisis de la composición corporal, en casos de alteraciones importantes en la composición corporal y/o el balance hídrico.
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