Diagnostic criteria for eating disorders

Established criteria for diagnosing anorexia nervosa and bulimia nervosa may be too strict, as many patients not meeting the full criteria are actually quite ill, say researchers.

A large study examined records from 1,310 female adolescent patients treated for eating disorders at Lucile Packard Children’s Hospital (LPCH), Stanford, California, US, between 1997 and 2008, and found that nearly two-thirds had been diagnosed under the medically heterogeneous category of Eating Disorder Not Otherwise Specified (EDNOS), with the remainder diagnosed as having either anorexia nervosa or bulimia nervosa. Importantly, 60 percent of the EDNOS patients met medical criteria for hospitalization and on average, this group was sicker than patients with a full diagnosis of bulimia. [Pediatrics 2010;125(5):e1193-1201]

Patients with eating disorders who end up with an EDNOS diagnosis are prone to being overlooked by clinicians and health insurers, said lead author Dr. Rebecka Peebles, an instructor in pediatrics at Stanford University, Mountain View, California, and an adolescent medicine specialist with the Comprehensive Eating Disorders Program at LPCH. “It is a bit misleading to patients – it can make them feel like they don’t have a real eating disorder,” she said.

“There’s mounting evidence that we should reconsider the EDNOS categorization for young people.”

More common among females than males, eating disorders can cause serious long term health problems and may even lead to death in some cases. In teenage girls, the prevalence of anorexia and bulimia is about 1 percent and 2-to-5 percent, respectively.

The existing methods of diagnosing these diseases were developed by expert consensus, not based on data derived from ongoing studies tracking patients’ health. To be diagnosed with anorexia in the US, a patient must be less than 85 percent of their expected body weight, have been without menstrual periods for at least 3 months, and have a fear of weight gain despite being “dangerously” thin. A bulimia diagnosis is given to patients who repeatedly “binge” on large quantities of food, then “purge” the added calories by vomiting.

“Our purpose was to ask if the diagnostic criteria now in use are really separating out the sickest of the sick,” said Peebles. In this study, the researchers also monitored for signs of malnutrition such as slow heart rate, low blood pressure, low body temperature, low blood levels of potassium and phosphorus, and prolonged QT interval.

The study found that many of the sickest EDNOS patients were being overlooked, despite manifesting criteria of severe malnutrition, suggesting that current medical criteria for evaluating eating disorders should be re-evaluated. “These findings illustrate the arbitrary nature of those cutoffs,” Peebles concluded.

Dr. Geraldine Lobo of the Medical City in the Philippines agrees that the current diagnostic criteria are limiting. “The criteria should really just serve as a guide and in the end, we essentially rely on our best clinical judgment in deciding how to help our patients.”

Source: Medical Tribune