Focus on weight loss, not admission weight, in eating disorder management

Melissa Whitelaw, BAppSc (Phys Ed), BAppSc (Hlth Sc), BNutrDiet, APD

Andrea K. Garber, PhD, RD

Clinicians need to look beyond a teenager’s weight at the time of a visit when screening for eating disorders, according to a new report, which reveals that recent weight loss trends and eating habits may be more predictive of a problem than actual weight.

The study, published in the Journal of Adolescent Health, found that teenagers with eating disorders who presented with higher recent weight loss-regardless of weight at the time of admission-had more complications from their disease.¹

The study analyzed records from nearly 200 12- to 19-year-olds hospitalized with anorexia nervosa or atypical anorexia nervosa. The research team found only a small association between weight and hypophosphatemia, according to the report, but a much greater association between recent weight loss and bradycardia.

Lead study author Melissa Whitelaw, BAppSc (Phys Ed), BAppSc (Hlth Sc), BNutrDiet, APD, is a private practitioner at the Melbourne Children’s Clinic, Camberwell, Victoria, Australia, and a registered dietician in the Department of Adolescent Medicine at the Royal Children’s Hospital, Melbourne. She says that although being underweight is a requirement for the diagnosis of anorexia nervosa, atypical anorexia nervosa-a recently identified eating disorder-meets all the criteria for anorexia nervosa without the low weight. This study found that these patients represented 31% of hospital admissions in teenagers over a 9-year period, and that there was a 5-fold increase in these cases over the study period.

“An awareness of this eating disorder is important for all pediatricians,” Whitelaw says. “With the backdrop of increasing prevalence of overweight and obesity, pediatricians should be alert to the possibility that weight loss in an adolescent could be a serious eating disorder despite the adolescent not being underweight and could even be overweight or obese.”

Danger signs

Whitelaw says the research revealed that greater total weight loss and recent weight loss, not the degree of underweight, were associated with life-threatening low pulse rates.

“This is a very serious cardiovascular complication that can be life threatening and requires hospitalization for monitoring and treatment. Greater severity of eating disorder cognitions was associated with greater recent weight loss, but not weight,” Whitelaw says. “No complication was independently associated with low admission weight. In other words, anorexia nervosa symptoms are associated with weight loss, not emaciation.”

Whitelaw says she hopes the study will highlight atypical presentations of anorexia for clinicians and help them realize that all weight loss-even that recommended by a clinician-should be monitored in adolescents. Assessment should first be done on the appropriateness of weight loss, and then to monitor progress and strategies used to achieve that loss, she says.

“The historical reliance on underweight as a measure of malnutrition has become less relevant in the context of obesity and weight loss. I hope that future consideration will be given to redefine the current diagnostic criterion in anorexia nervosa of ‘underweight’ to weight loss,” Whitelaw says. “With greater recognition of malnutrition at any size, I hope that there will be earlier identification and commencement of treatment for eating disorders in higher-weight adolescents. This is important because earlier commencement of treatment has been associated with better outcomes in adolescents.”

Recognizing atypical anorexia nervosa

Andrea K. Garber, PhD, RD, associate professor of Pediatrics, Division of Adolescent and Young Adult Medicine, University of California, San Francisco (UCSF) and UCSF Benioff Children’s Hospital, wrote a commentary² to accompany Whitelaw’s report and agrees that increased recognition of atypical anorexia nervosa-added to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) here in the United States in 2013-is important.

“This group of atypical kids has really expanded the recognition of this diagnosis,” Garber says. “The Whitelaw study helps to dispel the myth that atypical anorexia is like an ‘early anorexia.’ In fact, it is really full-blown anorexia nervosa in kids that start out at a higher weight.”

A previous study by the same group showed that 70% of patients with atypical anorexia start out in the overweight or obese range, she says.

“These patients are technically at normal weight, but are medically unstable,” Garber notes. “[Their presentation weight] doesn’t reflect the severity of their malnutrition.”

The study shows that bradycardia during refeeding was more often predicted by recent weight loss rather than by weight at the time of hospitalization, highlighting the need to reconsider clinical management of these patients, Garber says. The traditional clinical approach for anorexia has been to use presentation weight as the best indicator for risk, she adds.

“This study really demonstrates that weight history is important in the assessment of malnutrition across the range of [body mass indexes],” Garber says, adding that clinicians should be looking at objective data such as growth charts for these patients, as well as questioning patients and parents about recent weight trends. “Pediatricians need to be asking parents about weight history. Gone are the days that we just look at the numbers coming in. We need to be adding screening questions for parents about the starting point.”

References:

1. Whitelaw M, Lee KJ, Gilbertson H, Sawyer SM. Predictors of complications in anorexia nervosa and atypical anorexia nervosa: degree of underweight or extent and recency of weight loss? J Adolesc Health. 2018;63(6):717-723.

2. Garber AK. Moving beyond “skinniness”: presentation weight is not sufficient to assess malnutrition in patients with restrictive eating disorders across a range of body weights. J Adolesc Health. 2018;63(6):669-670.