Factors associated with refeeding hypophosphatemia in adolescents and young adults hospitalized with anorexia nervosa

Sex differences in electrolyte abnormalities indicating refeeding syndrome risk among hospitalized adolescents and young adults with eating disorders

BACKGROUND

Refeeding syndrome is the gravest possible medical complication in malnourished patients undergoing refeeding in the hospital. We previously reported that males with malnutrition secondary to eating disorders required more calories and had longer hospital stays than females; however, sex differences in electrolyte abnormalities indicating refeeding syndrome risk remain unknown. The objective of this study was to assess differences in electrolyte abnormalities indicating refeeding syndrome risk among male and female adolescents and young adults with eating disorders hospitalized for medical instability.

METHODS

We retrospectively reviewed the electronic medical records of 558 patients aged 9-25 years admitted to the University of California, San Francisco Eating Disorders Program for medical instability between May 2012 and August 2020. Serum was drawn per standard of care between 5 and 7 am each morning and electrolyte abnormalities indicating refeeding syndrome risk were defined as: hypophosphatemia (< 3.0 mg/dL), hypokalemia (< 3.5 mEq/L), and hypomagnesemia (< 1.8 mg/dL). Logistic regression was used to assess factors associated with electrolyte abnormalities indicating refeeding syndrome risk.

RESULTS

Participants included 86 (15.4%) males and 472 (84.6%) females, mean (SD) age 15.5 (2.8) years. Rates of refeeding hypophosphatemia (3.5%), hypokalemia (8.1%), and hypomagnesemia (11.6%) in males hospitalized with eating disorders were low, with no statistically significant differences from females. Older age was associated with higher odds of refeeding hypophosphatemia and hypomagnesemia. Lower percent median body mass index and greater weight suppression at admission were associated with higher odds of refeeding hypophosphatemia.

CONCLUSIONS

Rates of electrolyte abnormalities indicating refeeding syndrome risk were low in males hospitalized for eating disorders and rates did not significantly differ from females. Together with our finding that males have higher caloric requirements and longer hospital length of stay, the finding that electrolyte abnormalities indicating refeeding syndrome risk were not greater in males than females supports future research to evaluate the safety and efficacy of higher calorie and/or faster advancing refeeding protocols for males.

Inpatient treatments for adults with anorexia nervosa: a systematic review of literature

PURPOSE

Anorexia nervosa (AN) is a mental disorder for which hospitalization is frequently needed in case of severe medical and psychiatric consequences. We aim to describe the state-of-the-art inpatient treatment of AN in real-world reports.

METHODS

A systematic review of the literature on the major medical databases, spanning from January 2011 to October 2023, was performed, using the keywords: "inpatient", "hospitalization" and "anorexia nervosa". Studies on pediatric populations and inpatients in residential facilities were excluded.

RESULTS

Twenty-seven studies (3501 subjects) were included, and nine themes related to the primary challenges faced in hospitalization settings were selected. About 81.48% of the studies detailed the clinical team, 51.85% cited the use of a psychotherapeutic model, 25.93% addressed motivation, 100% specified the treatment setting, 66.67% detailed nutrition and refeeding, 22.22% cited pharmacological therapy, 40.74% described admission or discharge criteria and 14.81% follow-up, and 51.85% used tests for assessment of the AN or psychopathology. Despite the factors defined by international guidelines, the data were not homogeneous and not adequately defined on admission/discharge criteria, pharmacological therapy, and motivation, while more comprehensive details were available for treatment settings, refeeding protocols, and psychometric assessments.

CONCLUSION

Though the heterogeneity among the included studies was considered, the existence of sparse criteria, objectives, and treatment modalities emerged, outlining a sometimes ambiguous report of hospitalization practices. Future studies must aim for a more comprehensive description of treatment approaches. This will enable uniform depictions of inpatient treatment, facilitating comparisons across different studies and establishing guidelines more grounded in scientific evidence.

LEVEL OF EVIDENCE

Level I, systematic review.

A prospective observational study examining weight and psychosocial change in adolescent and adult eating disorder inpatients admitted for nutritional rehabilitation using a high-energy re-feeding protocol

BACKGROUND

High-energy re-feeding protocols are increasingly utilised for nutritional rehabilitation in adolescents with anorexia nervosa (AN), however, concern persists that adults with AN may be at greater risk of developing complications. In addition, research on psychological outcomes of eating disorder (ED) inpatient treatment programs, and outcomes of high-energy protocols in avoidant restrictive food intake disorder (ARFID) and bulimia nervosa (BN), is limited. This study of an ED inpatient program using a high-energy protocol, compared changes in weight and psychosocial outcomes between adolescents and adults, and identified medical risk factors associated with deviation from the protocol.

METHOD

This prospective observational study took place in a voluntary ED treatment program in a private hospital. Weight, height, and psychosocial questionnaires (ED Examination-Questionnaire, Depression Anxiety Stress Score, Clinical Impairment Assessment and AN/BN Stage of Change) were collected from consenting adolescents (16-20 years) and adults (> 20 years) on admission and discharge. Medical tolerance to the high-energy protocol was assessed daily. Independent samples t-tests and paired samples t-tests were applied to normally distributed data, and Mann-Whitney U tests and Wilcoxon signed-rank tests to skewed data. P-values < 0.05 were considered significant statistically.

RESULTS

Ninety-seven participants were recruited. The majority (n = 91, 94%) were female and most (n = 80, 83%) had AN. Forty-two (43%) were adolescents and 55 (57%) were adults. In participants with AN, weight change (Δ) was significant [median Δ 8.0 (interquartile range (IQR) 4.3) kg]. There was no difference in rate of weight change between adolescents and adults with AN [mean Δ 1.8 (standard deviation (SD) 0.5) kg/week vs. Δ 1.8 (SD 0.6) kg/week; p = 0.841, respectively]. One (1%) participant with AN did not tolerate the high-energy protocol due to oedema. Participants achieved positive change in psychosocial questionnaire scores (p < 0.001) after the the specialist ED program, with no difference between adolescents and adults (p > 0.05).

CONCLUSIONS

This voluntary ED treatment program using a high energy re-feeding protocol was effective in achieving positive weight and psychological change for adolescents and adults with minimal adverse events. This indicates that the specialist ED program has both nutritional and psychological benefits.

Refeeding Syndrome in Pediatric Age, An Unknown Disease: A Narrative Review

Refeeding syndrome (RS) is characterized by electrolyte imbalances that can occur in malnourished and abruptly refed patients. Typical features of RS are hypophosphatemia, hypokalemia, hypomagnesemia, and thiamine deficiency. It is a potentially life-threatening condition that can affect both adults and children, although there is scarce evidence in the pediatric literature. The sudden increase in food intake causes a shift in the body's metabolism and electrolyte balance, leading to symptoms such as weakness, seizures, and even heart failure. A proper management with progressive increase in nutrients is essential to prevent the onset of this condition and ensure the best possible outcomes. Moreover, an estimated incidence of up to 7.4% has been observed in pediatric intensive care unit patients receiving nutritional support, alone or as an adjunct. To prevent RS, it is important to carefully monitor feeding resumption, particularly in severely malnourished individuals. A proper strategy should start with small amounts of low-calorie fluids and gradually increasing the calorie content and amount of food over several days. Close monitoring of electrolyte levels is critical and prophylactic use of dietary supplements such as thiamine may be required to correct any imbalances that may occur. In this narrative review, we aim to provide a comprehensive understanding of RS in pediatric clinical practice and provide a possible management algorithm.

Vitamin D and hypophosphatemia in patients with anorexia nervosa and avoidant/restrictive food intake disorder: a case control study

BACKGROUND

Refeeding hypophosphatemia (RH) is a common complication of nutritional restoration in malnourished individuals, yet clear risk stratification remains elusive. Individuals with anorexia nervosa (AN) and avoidant/restrictive food intake disorder (ARFID) may be deficient in vitamin D, an important component of dietary phosphorus absorption in the gut. The relationship between vitamin D and RH in AN and ARFID is unknown. Therefore, the aims of this study were to (1) report rates of low serum 25-hydroxy vitamin D and RH in AN and ARFID; (2) describe associations between phosphorus and variables associated with RH identified in extant literature; (3) examine the relationship between 25-hydroxy vitamin D and RH and (4) investigate moderation by vitamin D between variables of interest and phosphorus level.

METHOD

Analyses included retrospective chart review of 307 individuals admitted to the ACUTE Center for Eating Disorders and Severe Malnutrition with a diagnosis of AN or ARFID. Variables of interest included admission laboratory values (vitamin D level, comprehensive metabolic panel, hemoglobin, point-of-care blood glucose), anthropometric measures (weight, body mass index [BMI], % ideal body weight [IBW]), age, duration of illness, length of stay, feeding method, and serum phosphorus nadir. Pearson and Spearman rank correlation, one-way ANOVA, and regression analyses were used to determine the relationship between variables and serum phosphorus.

RESULTS

Over 1/3 of the sample (35.3%) had serum phosphorus levels ≤ 2.9 mg/dL. There were no significant differences between groups in phosphorus nadir (p = .17, η2 = 0.12) or hypophosphatemia (p = .16, ϕc = 0.11). Thirty-five (35%) of individuals with ARFID were either deficient or insufficient in vitamin D, compared to 29% of individuals with AN. Individuals with AN had significantly higher mean vitamin D levels compared to those with ARFID (p = .03; η2 = 0.015). Nadir phosphorus showed a positive association with weight, BMI, %IBW, potassium, and calcium on admission, and a negative association with length of stay, hemoglobin, and total number of tube-fed days. Higher levels of 25-hydroxy vitamin D moderated the relationship between serum phosphorus nadir and weight on admission (p = .0004).

CONCLUSION

Individuals diagnosed with ARFID are as nutritionally fragile as those with AN regarding vitamin D and RH. The negative feedback loop involving vitamin D that maintains phosphorus homeostasis may play a role in the development of RH in AN and ARFID.

Characterization of refeeding protocols for under 18 years old hospitalized patients with anorexia nervosa: A systematic review

PURPOSE

To characterize and compare, through descriptive analysis, existing refeeding protocols for under 18 years old hospitalized patients with anorexia nervosa (AN).

METHODS

This is a systematic review of PubMed, Cochrane, SciELO, Lilacs and BVS databases, without search period restriction. Studies were selected in accordance with pre-defined eligibility criteria and according to the Population, Intervention, Comparator, Outcome and Study Design (PICOS).

RESULTS

Twenty articles out of 412 found complied with PICOS eligibility criteria and were included in the final review. Most of the studies were observational or retrospective and 80% were published in the last decade. Large variability in relation to sample size, refeeding protocols and length of stay were observed between studies.

CONCLUSION

All included studies had several methodological limitations and heterogeneous designs, making it difficult to establish conclusive guidelines regarding the most adequate and effective refeeding protocol for under 18 years old hospitalized patients with AN. Prospective trials are necessary to straight compare standard refeeding protocols for this population.

Vitamin D and Hypophosphatemia in Patients with Anorexia Nervosa and Avoidant/Restrictive Food Intake Disorder: A Case Control Study

Background

Refeeding hypophosphatemia (RH) is a common complication of nutritional restoration in malnourished individuals, yet clear risk stratification remains elusive. Individuals with anorexia nervosa (AN) and avoidant/restrictive food intake disorder (ARFID) may be deficient in vitamin D, an important component of dietary phosphorus absorption in the gut. The relationship between vitamin D and RH in AN and ARFID is unknown. Therefore, the aims of this of this study were to 1) describe the prevalence of low serum 25-hydroxy vitamin D levels and RH in AN and ARFID 2) report associations between nadir phosphorus level and variables associated with RH in extant literature and 3) examine the relationship between 25-hydroxy vitamin D levels and serum phosphorus nadir in AN and ARFID.

Method

Analyses included retrospective chart review of 307 individuals admitted to the ACUTE Center for Eating Disorders and Severe Malnutrition with a diagnosis of AN or ARFID. Variables of interest included admission laboratory values (vitamin D level, comprehensive metabolic panel, hemoglobin, point-of-care blood glucose), anthropometric measures (weight, body mass index [BMI], % ideal body weight [IBW]), age, duration of illness, length of stay, feeding method, and serum phosphorus nadir. Pearson and Spearman rank correlation, one-way ANOVA, and regression analyses were used to determine the relationship between variables and serum phosphorus.

Results

Over 1/3 of the sample (35.3%) had serum phosphorus levels ≤ 2.9 mg/dL. There were no significant differences between groups in phosphorus nadir (p = .17, η2 = 0.12) or hypophosphatemia (p = .16, ϕc = 0.11); 44% of individuals with ARFID and 33% of individuals with AN had hypophosphatemia. Nadir phosphorus showed a positive association with weight, BMI, %IBW, potassium, and calcium on admission, and a negative association with length of stay, hemoglobin, and total number of tube-fed days. Higher levels of 25-hydroxy vitamin D moderated the relationship between serum phosphorus nadir and weight on admission (p = .0004).

Conclusion

Individuals diagnosed with ARFID are as nutritionally fragile as those with AN regarding vitamin D and RH. The negative feedback loop involving vitamin D that maintains phosphorus homeostasis may play a role in the development of RH in AN and ARFID.

Outcomes of a Standardized, High-Caloric, Inpatient Re-Alimentation Treatment Protocol in 120 Severely Malnourished Adolescents with Anorexia Nervosa

Evidence accumulates that, with close medical monitoring and phosphate supplementation, higher-caloric re-alimentation protocols beginning at 2000 kcal/day (HCR) are not associated with an increased incidence of electrolyte abnormalities in patients with anorexia nervosa (AN) but rather result in faster weight gain. These studies are still scant and have largely been performed in adults or moderately malnourished adolescents. Methods: A retrospective chart review of patients with AN aged 12−20 years and with a body mass index (BMI) < 15 kg/m2 alimented according to a standardized treatment protocol in a German clinic specialized in AN was conducted. All patients received 2000 kcal/day from day one. The effect of HCR was examined with respect to laboratory changes and weight development over 4 weeks. Results: In 120 youth (119 (99.2%) females and 1 (0.8%) male, the mean BMI was 13.1 ± 1.1 (range = 10.2−15.0), %mBMI was 62.1 ± 6.0% and weight gain was 0.76 ± 0.22 kg per week, with the highest rate of weight gain during week 1 (1.25 ± 1.28 kg/week). Over 4 weeks, the total weight gain was 3.00 ± 1.92 kg. Nine patients (7.5%) developed mild hypophosphatemia, and none developed refeeding syndrome. Conclusions: Starting re-alimentation with 2000 kcal/d under close medical surveillance, severely malnourished youth with AN met the recommended weight gain targets between 0.5 and 1 kg/week according to current treatment guidelines, without anyone developing refeeding syndrome.