Anthropometrical and Bioelectrical Impedance Analysis Parameters in Anorexia Nervosa Patients' Nutritional Status Assessment.

Background and Objectives: Body mass index (BMI) is still the only recommended measurable nutritional status assessment parameter in anorexia nervosa (AN). The aim of this study was to measure other anthropometrical and bioelectrical impedance analysis (BIA) parameters in AN patients and to evaluate their nutritional status assessment value. Materials and Methods: The 46 AN female patients were examined at the beginning of hospitalization and followed-up in three measurements (in 6 ± 2 weeks' intervals). Anthropometrical assessment was based on BMI, circumferences of arm, calf, thigh, hips, waist, their ratio (waist-to-hip ratio (WHR)), and a skinfold test over biceps and triceps muscle, under the scapula, over the hip, and 2 cm from the umbilicus. The BIA parameters included phase angle (PA), membrane capacitance (Cm), and impedance at 200 kHz, and a 5 kHz ratio (Z200/5). Results: In the 1st measurement, BMI correlated with all anthropometric and BIA parameters (p < 0.05). For BIA parameters, the correlation included arm circumference and WHR (p < 0.05). In the follow-up, significant changes were observed in BMI and all BIA parameters. The correlation between BMI and all BIA parameters was present in the 2nd and 3rd measurements (p < 0.05). In the 4th measurement, BMI correlated only with Cm (p = 0.0114). Comparison of BIA parameters according to the state of starvation (BMI < 16.0 kg/m2) revealed that all studied BIA parameters were characterized by statistically significant sensitivity and specificity in the detection of this condition (p < 0.05), except PA in the 4th measurement (p = 0.2099). Conclusions: Selected BIA and anthropometrical parameters could be used for AN patients' assessment. The study confirmed dynamic changes of BIA parameters during the follow-up. They could be useful in the detection of the state of starvation.

Application of phase angle for evaluation of the nutrition status of patients with anorexia nervosa. / Wykorzystanie kata fazowego do oceny stanu odzywienia pacjentów z jadlowstretem psychicznym.

The evaluation of the nutrition status of patients has been the subject of interest of many scientific disciplines. Any deviation from normal values is a serious clinical problem. There are multiple nutrition status evaluation methods used including diet history, scales and questionnaires, physical examination, anthropometric measurements, biochemical measurements, function tests, as well as bioelectric impedance analysis or adipometry. Phase angle, obtained by means of bioelectric impedance analysis, is another parameter that is being more and more frequently applied in nutrition status monitoring. It is proportional to body cell mass. Its direct correlation with the cellular nutrition status has been documented. High phase angle values signify well-being, while low phase angle values indicate poor condition of cells. The purpose of this paper was to review the current state of knowledge about the application of phase angle in evaluation and monitoring of the nutrition status of patients with anorexia nervosa on the basis of available literature. It was proven that the phase angle values in patients with anorexia nervosa are much lower compared to healthy people. Detailed observations showed phase angle value increase in the course of treatment. The relevance of the commonly used body mass index (BMI) has been questioned due to significant degree of generalization in the nutrition status evaluation. Thus, there is a need for new, objective parameters for nutrition status evaluation, which will assist in the treatment and monitoring of patients in a more meaningful and reliable way. The existing independent studies equivocally confirm the usefulness of phase angle in the evaluation of nutrition status of patients with anorexia nervosa and its broader application in clinical practice is only a matter of time. However, these are merely attempts and they have not yet found wider application in clinical practice in the treatment of anorexia nervosa.