Rapid renutrition improves health status in severely malnourished inpatients with AN - score-based evaluation of a high caloric refeeding protocol in severely malnourished inpatients with anorexia nervosa in an intermediate care unit

The incidence of refeeding syndrome and the nutrition management of severely malnourished inpatients with eating disorders: An observational study

OBJECTIVE

Nutritional rehabilitation and weight restoration are often critical for the treatment of eating disorders (ED), yet are restricted by the potential risk of refeeding syndrome (RFS). The primary objective was to determine the incidence of RFS. Secondary objectives were to explore predictive factors of RFS and describe its impact on treatment goals for patients with ED.

METHOD

This retrospective observational study reviewed the nutrition management for patients admitted to a quaternary hospital for ED treatment from 2018 to 2020. Data were collected during the first 4 weeks of admission and included anthropometry, energy prescription, incidence and severity of RFS, and electrolyte and micronutrient prescription. Outcomes included incidence of RFS, energy prescription and advancement, and weight change.

RESULTS

Of 423 ED admissions, 217 patients (median [interquartile range, IQR] age 25 [21-30.5] years; 210 [97%] female) met inclusion criteria. Median (IQR) body mass index (BMI) on admission was 15.5 (14.1-17.3) kg/m2 . The mean (standard deviation) length of admission was 35 (7.3) days. Median (IQR) initial energy prescription was 1500 (930-1500) kcal/day. Seventy-three (33%) patients developed RFS; 34 (16%) mild, 27 (12%) moderate, and 12 (5%) severe. There was no association between RFS severity and admission BMI, energy prescription, or prescription of prophylactic electrolytes or micronutrients. Lower admission weight was associated with RFS (odds ratio 0.96, 95% confidence interval [0.93-1.00], p = .035). Less than half of the participants met the weight gain target (>1 kg per week) in the first 3 weeks of admission.

DISCUSSION

The incidence of severe RFS was low in this cohort and was associated with lower admission weight.

PUBLIC SIGNIFICANCE

This study is one of the largest studies to utilize consensus-defined criteria to diagnose RFS among adult patients admitted for treatment of an ED. This population is still considered to be at risk of RFS and will require close monitoring. The results add to the growing body of research that restriction of energy prescription to prevent RFS may not require the level of conservatism traditionally practiced.

Health Risk and Underweight

Anorexia nervosa is associated with a significant risk of morbidity and mortality. In clinical practice, health risk is assessed and estimated using routinely collected laboratory data. This study will develop a risk score using clinically relevant laboratory parameters. The related question is how to estimate the health risk associated with underweight using body weight, height and age.

METHODS

We used routinely collected laboratory parameters from a total of 4087 patients. The risk score was calculated on the basis of electrolytes, blood count, transaminases and LDH. The nine parameters used were summed as zlog-transformed values. Where appropriate, the scales were inverted so that high values represented higher risk. For statistical prediction of the risk score, weight/height and age reference values from the WHO, the CDC (Center of Disease Control) and representative studies of German children and adults (KIGGS and NNS) were used.

RESULTS

The score calculated from nine laboratory parameters already shows a convincing relationship with BMI. Among the weight measures used for height and age, the z-score from the CDC reference population emerged as the best estimate, explaining 34% of the variance in health risk measured by the laboratory score. The percentile rank for each age-specific median weight from the KIGGS/NNS still explained more than 31% of the variance. In contrast, percentiles explained less variance than BMI without age correction.

CONCLUSIONS

The score we used from routine laboratory parameters appears to be an appropriate measure for assessing the health risk associated with underweight, as measured by the quality of the association with BMI. For estimating health risk based on weight, height and age alone, z-scores and percentages of age-specific median weight, as opposed to percentiles, are appropriate parameters. However, the study also shows that existing age-specific BMI reference values do not represent risk optimally. Improved statistical estimation methods would be desirable.

Liver Damage Is Related to the Degree of Being Underweight in Anorexia Nervosa and Improves Rapidly with Weight Gain

Background: The present study investigates the relationship between hypertransaminasemia and malnutrition on the basis of a very large number of patients. We assume that the level of transaminases not only reflects the extent of underlying liver cell damage but also provides information about the metabolic situation under conditions of energy deficiency. Methods: We present an observational study in two different samples. The first sample consists of 3755 patients (mean age 22.7 years, Range 12−73 years; mean BMI 15.4 kg/m2, range 8.1−25.7) out of a total of 4212 patients with anorexia nervosa treated in the Roseneck Clinic within five years for whom a complete admission laboratory was available. The second sample was obtained from a special ward for medically at-risk patients with eating disorders. During the period in question, four hundred and ten patients with anorexia nervosa were treated. One hundred and forty-two female patients (mean age 26.4 years, Range 18−63 years; mean BMI 11.5 kg/m2, range 8.4−13) had a BMI of thirteen or less and a complete data set was obtained at admission and weekly in the following four weeks after admission. Results: The increase in liver transaminases shows a very high correlation with weight in sample one (N = 3755). The analysis of variance shows highly significant (<0.001) correlations with an F-value of 55 for GOT/AST and 63 for GPT/ALT. Nevertheless, the variance within the groups with the same BMI is quite high. With re-nutrition in sample two, GOT/AST decreased on average from 71 U/L to 26 U/L (MANOVA F 10.7, p < 0.001) and GPT/ALT from 88 to 41 U/L (F = 9.9, p < 0.001) within four weeks. Discussion: Below a BMI of about 13, the nutritional status of the patients becomes so critical that the energy supply of the patient is increasingly dependent on the autophagy of the liver, which can be seen in the very strong increase in transaminases here. Refeeding leads very quickly to the normalisation of the transaminases and, thus, a stabilisation of the metabolism leading also to a decrease in autophagy.