Energy expenditure in anorexia nervosa: can fat-free mass as measured by bioelectrical impedance predict energy expenditure in hospitalized patients?

Energy expenditure during nutritional rehabilitation: a scoping review to investigate hypermetabolism in individuals with anorexia nervosa

BACKGROUND

Weight gain and nutritional rehabilitation are essential first steps to achieve medical stabilization in anorexia nervosa, and frequent resistance to weight gain requires patients to consume high kilocalorie loads. Adaptive hypometabolism is common when patients begin treatment, and rebound hypermetabolism is suspected to be a significant barrier to weight gain. The aim of this review was to summarize existing data describing metabolic changes in anorexia nervosa during weight restoration. The reported findings challenge current hypotheses of weight gain resistance and highlight key areas for future research.

METHODS

Using scoping review guidelines, three databases were searched for studies investigating metabolic changes in anorexia nervosa before and after renourishment. Two reviewers systematically screened the titles and abstracts of 447 articles, and full-text versions of 106 studies were assessed for eligibility. A total of 36 studies were included for review. Data regarding the study description, sample population (including age, weight, BMI, duration of treatment, and caloric intake), and metabolic variable descriptions were extracted.

RESULTS

Female patients with anorexia nervosa from studies across 13 countries were included. Across the studies, average BMI increased from 13.7 kg/m2 at admission to 17.57 kg/m2. Patients presented to treatment with clinically reduced energy expenditure levels. After varying levels of nutritional rehabilitation and weight restoration, measured energy expenditure increased significantly in 76% of the studies. Energy expenditure values at the second timepoint increased to the standard range for normal weight female teenagers and adults. Despite these increases, the studies do not indicate the presence of a hypermetabolic state during renourishment. Additionally, all studies including both measured and predicted energy expenditure reported that predicted energy expenditure overestimated measured values.

CONCLUSION

This study provides a detailed evaluation of the literature investigating energy expenditure and metabolic rate in patients with anorexia nervosa before and following a period of renourishment. The findings from this review identify important gaps in the current beliefs of energy expenditure in anorexia nervosa and highlight a need for further exploration of metabolic alterations during weight restoration.

Refeeding Low Weight Hospitalized Adolescents With Anorexia Nervosa: A Multicenter Randomized Controlled Trial

BACKGROUND

Refeeding patients with anorexia nervosa (AN) is associated with high morbidity and mortality. A lack of evidence from interventional studies has hindered refeeding practice and led to worldwide disparities in management recommendations. In the first randomized controlled trial in this area, we tested the hypothesis that refeeding adolescents with AN with a higher energy intake than what many guidelines recommend improved anthropometric outcomes without adversely affecting cardiac and biochemical markers associated with refeeding.

MATERIALS AND METHODS

Participants aged 10-16 years with a body mass index (BMI) <78% of the median (mBMI) for age and sex were recruited from 6 UK hospitals and randomly allocated to start refeeding at 1200 kcal/d (n = 18, intervention) or 500 kcal/d (n = 18, control).

RESULTS

Compared with controls, adolescents randomized to high energy intake had greater weight gain (mean difference between groups after 10 days of refeeding, -1.2% mBMI; 95% confidence interval, -2.4% to 0.0%; P = .05), but randomized groups did not differ statistically in QTc interval and other outcomes. The nadir in postrefeeding phosphate concentration was significantly related to percentage mBMI at the start of refeeding (baseline; P = .04) and baseline white blood cell count (P = .005) but not to baseline energy intake (P = .08).

CONCLUSIONS

Refeeding adolescents with AN with a higher energy intake was associated with greater weight gain but without an increase in complications associated with refeeding when compared with a more cautious refeeding protocol-thus challenging current refeeding recommendations.

Refeeding hypophosphatemia in adolescents with anorexia nervosa: a systematic review

The rate of adolescents presenting with anorexia nervosa (AN) is increasing. Medically unstable adolescents are admitted to the hospital for nutrition restoration. A lack of global consensus on appropriate refeeding practices of malnourished patients has resulted in inconsistent refeeding practices. Refeeding hypophosphatemia (RH) is the most common complication associated with refeeding the malnourished patient. This review sought to identify the range of refeeding rates adopted globally and the implication that total energy intake and malnutrition may have on RH while refeeding adolescents with anorexia nervosa. Studies were identified by a systematic electronic search of medical databases from 1980 to September 2012. Seventeen publications were identified, including 6 chart reviews, 1 observational study, and 10 case reports, with a total of 1039 subjects. The average refeeding energy intake was 1186 kcal/d, ranging from 125-1900 kcal/d, with a mean percentage median body mass index (% mBMI) of 78%. The average incidence rate of RH was 14%. A significant correlation between malnutrition (% mBMI) and post-refeeding phosphate was identified (R (2) = 0.6, P = .01). This review highlights the disparity in refeeding rates adopted internationally in treating malnourished adolescents with anorexia nervosa. Based on this review, the severity of malnutrition seems to be a marker for the development of RH more so than total energy intake.

Body composition: why, when and for who?

Body composition reflects nutritional intakes, losses and needs over time. Undernutrition, i.e. fat-free mass (FFM) loss, is associated with decreased survival, worse clinical outcome and quality of life, as well as increased therapy toxicity in cancer patients. In numerous clinical situations, such as sarcopenic obesity and chronic diseases, the measurement of body composition with available methods, such as dual-X ray absorptiometry, computerized tomography and bioelectrical impedance analysis, quantifies the loss of FFM, whereas body weight loss and body mass index only inconstantly reflect FFM loss. The measurement of body composition allows documenting the efficiency of nutrition support, tailoring the choice of disease-specific and nutritional therapies and evaluating their efficacy and putative toxicity. Easy-to-use body composition methods integrated to the routine of care allow sequential measurements for an initial nutritional assessment and objective patients follow-up. By allowing an earlier and objective management of undernutrition, body composition assessment could contribute to reduce undernutrition-induced morbidity, worsening of quality of life, and global health care costs by a timely nutrition intervention.

A prospective examination of weight gain in hospitalized adolescents with anorexia nervosa on a recommended refeeding protocol

PURPOSE

Current refeeding recommendations for adolescents hospitalized with anorexia nervosa (AN) are conservative, starting with low calories and advancing slowly to avoid refeeding syndrome. The purpose of this study was to examine weight change and clinical outcomes in hospitalized adolescents with AN on a recommended refeeding protocol.

METHODS

Adolescents aged 13.1-20.5 years were followed during hospitalization for AN. Weight, vital signs, electrolytes, and 24-hour fluid balance were measured daily. Percent median body mass index (%MBMI) was calculated as 50th percentile BMI for age and gender. Calories were prescribed on admission and were increased every other day.

RESULTS

Thirty-five subjects with a mean (SD) age of 16.2 (1.9) years participated over 16.7 (6.4) days. Calories increased from 1,205 (289) to 2,668 (387). No subjects had refeeding syndrome; 20% had low serum phosphorus. Percent MBMI increased from 80.1 (11.5) to 84.5 (9.6); overall gain was 2.10 (1.98) kg. However, 83% of subjects initially lost weight. Mean %MBMI did not increase significantly until day 8. Higher calories prescribed at baseline were significantly associated with faster weight gain (p = .003) and shorter hospital stay (p = .030) in multivariate regression models adjusted for %MBMI and lowest heart rate on admission.

CONCLUSIONS

Hospitalized adolescents with AN demonstrated initial weight loss and slow weight gain on a recommended refeeding protocol. Higher calorie diets instituted at admission predicted faster weight gain and shorter hospital stay. These findings support the development of more aggressive feeding strategies in adolescents hospitalized with AN. Further research is needed to identify caloric and supplementation regimens to maximize weight gain safely while avoiding refeeding syndrome.

The evaluation of body composition: a useful tool for clinical practice

Undernutrition is insufficiently detected in in- and outpatients, and this is likely to worsen during the next decades. The increased prevalence of obesity together with chronic illnesses associated with fat-free mass (FFM) loss will result in an increased prevalence of sarcopenic obesity. In patients with sarcopenic obesity, weight loss and the body mass index lack accuracy to detect FFM loss. FFM loss is related to increasing mortality, worse clinical outcomes, and impaired quality of life. In sarcopenic obesity and chronic diseases, body composition measurement with dual-energy X-ray absorptiometry, bioelectrical impedance analysis, or computerized tomography quantifies the loss of FFM. It allows tailored nutritional support and disease-specific therapy and reduces the risk of drug toxicity. Body composition evaluation should be integrated into routine clinical practice for the initial assessment and sequential follow-up of nutritional status. It could allow objective, systematic, and early screening of undernutrition and promote the rational and early initiation of optimal nutritional support, thereby contributing to reducing malnutrition-induced morbidity, mortality, worsening of the quality of life, and global health care costs.

How accurate are predictive formulas calculating energy expenditure in adolescent patients with anorexia nervosa?

BACKGROUND & AIMS

To compare resting energy expenditure, measured by indirect calorimetry, to values estimated by different predictive formulas in adolescent patients with anorexia nervosa.

METHODS

We studied 22 female in-patients with a mean age of 14.7 years (SD 1.2). Resting energy expenditure was measured by indirect calorimetry (Deltatrac II MBM-200). We compared measured resting energy expenditure to values estimated by several predictive formulas [Fleisch, Harris-Benedict, FAO, Schofield-HW, Schebendach] using the intraclass correlation coefficient and the Bland-Altman method.

RESULTS

Body mass index increased significantly (P<0.001). Measured resting energy expenditure increased during hospitalization (P<0.05). All formulas overestimated resting energy expenditure with respect to indirect calorimetry except the Schebendach formula. The intraclass correlation between indirect calorimetry and the formulas were poor (0.09-0.20). We observed a poor clinical agreement (Bland-Altman).

CONCLUSIONS

Body mass index and resting energy expenditure increased during hospitalization. The majority of the predictive formulas overestimate resting energy expenditure in adolescent patients with anorexia nervosa. Therefore, indirect calorimetry may be a very useful tool for calculating caloric requirements in these patients.

Application criteria of enteral nutrition in patients with anorexia nervosa: correlation between clinical and psychological data in a "lifesaving" treatment

BACKGROUND

Data and research increasingly point to multiple factors in the genesis of eating-behavior disorders, but the lack of a clear etiological definition prevents a unique therapeutic or prognostic approach from being defined. Therapeutic approaches, as well as scientific research, have separately analyzed the psychological aspects and the clinical-nutrition aspects without integrating the variables or correlating clinical and psychological data. This work has several goals because it aims at considering the problem from the 2 different perspectives. Psychological and clinical variables are analyzed both separately and together in order to assess (a) the minimal criteria to define a cure as "lifesaving" and submit a patient to artificial nutrition; (b) the kind of implementation artificial nutrition should follow; (c) which indicators of the efficacy of artificial nutrition must be taken into account; (d) the results in nutrition terms that may be obtained during the follow-up; (e) if artificial nutrition may be used as a therapeutic tool; (f) if there are any psychological effects after artificial nutrition; (g) if there are any effects due to the patients' age; and (h) the correlation between the psychological profile of a patient and the acceptance of the nutrition treatment.

METHODS

Several psychological and pharmacologic variables, together with clinical and anthropometric data and blood chemical values, were all considered.

CONCLUSIONS

Besides defining minimal criteria for a "lifesaving" cure and proposing 2 ad hoc scales for the assessment of patients' subjective willingness toward feeding and for the objective measurement of feeding itself, clinical data and correlations with psychological data evidenced the importance of artificial nutrition and specifically of enteral nutrition as a therapeutic tool, allowing us to define the modalities of implementation of enteral nutrition. Results show that, because enteral nutrition did not deteriorate the psychological state of the patients, and was found to be accepted more positively than feeding orally in the most critical initial phase, it should be included in the therapy.

Medical assessment of adolescent girls with eating disorders: an evaluation of symptoms and signs of starvation

AIM

To investigate the prevalence of symptoms and signs related to starvation at the initial examination of adolescent girls with eating disorders (ED).

METHODS

Two hundred and eleven girls with eating disorders recruited for a multicentre research and evaluation programme of six specialist eating disorder services in Sweden have been studied. The presence or absence of 12 symptoms, reported by the patients, and 16 signs, observed by the examiners, were registered and related to body weight.

RESULTS

Eleven observed signs--loss of subcutaneous fat, loss of muscle mass, loss of muscular force, dry and scaly skin, brittle nails, dry and brittle hair, lanugo hair, resting pulse <60, systolic blood pressure <110, peripheral hypothermia, and peripheral cyanosis--were related to body weight expressed in standard deviation scores (SDS). When the number of observed signs for each patient was calculated, there was a strong relationship with weight. The odds ratio for having more than two signs was 4.35 (95% CI 2.67-7.04; p = 2.8 x 10(-9) for every one-unit change in weight SDS. Of the symptoms reported by the patients, only three were related to weight. When the number of reported symptoms for each patient was calculated, a relationship with weight was not observed.

CONCLUSION

In adolescent girls with ED, physical signs observed at medical examination can be related to weight. However, reported symptoms are poorly related to weight and may be influenced by other factors. The finding emphasizes the importance of medical assessment at presentation of patients with ED.

The prediction of basal metabolic rate in female patients with anorexia nervosa

OBJECTIVE

To evaluate in female patients with anorexia nervosa the accuracy of a specific predictive formula for basal metabolic rate (BMR) already proposed in the literature and to derive a new disease-specific equation with the same purpose.

DESIGN

Cross-sectional study.

SUBJECTS

One-hundred and twenty adolescent girls (<18 y) and young-adult women (18-30 y) with anorexia nervosa.

MEASUREMENTS

BMR was determined by indirect calorimetry or predicted according to the Schebendach formula, which was specifically derived for anorexia nervosa.

RESULTS

On average the Schebendach formula performed well in the adolescent group but not in the young-adult group. The range including 95% of the predicted-measured differences was in both cases wider than 2000 kJ/day. In the young-adult patients the accuracy of the prediction was also related to age and body mass index. Weight and age (but not height or body mass index) emerged as predictors of BMR in the sample as a whole, and only weight when the two age groups were considered separately, thus leading to three different equations. The intercepts of these regression lines were very close and not significantly different from zero while their standard error of estimate was 500-550 kJ/day.

CONCLUSION

The Schebendach formula is not very accurate in estimating the BMR of female anorectic patients. Moreover, in this group the relationship between BMR and weight was altered. The predictive formulas proposed by the present study have a reasonable prediction power.