“Underweight has traditionally been equated with a more serious illness,” said Dr. Andrea Garber, chief nutritionist at the UCSF Eating Disorders Program. “Currently, a third of admissions for eating disorders are patients with atypical anorexia nervosa with normal weight or above.
Dr. Garber and her colleagues compared weight loss and disease severity between two groups of patients ages 12 to 24 who had enrolled in a clinical trial upon entering the hospital for treatment.
“Our study suggests that patients with large, rapid, or prolonged weight loss are more severely ill, regardless of their current weight,” he said, noting that both groups lost about 30 pounds in about 15 months (Garber et al., 2019).
A group of 66 individuals with anorexia nervosa participated in the study, which excluded those who were extremely underweight; and another group with 50 heavier patients with so-called atypical anorexia nervosa.
Study participants were enrolled in the StRONG trial, a short-term nutritional refeeding or rehabilitation study, at UCSF Benioff Children’s Hospital San Francisco and Lucile Packard Children’s Hospital, Stanford.
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Of the total of 116 participants, 105 were women; half were white in the atypical group and two-thirds were white in the typical group.
They found that patients with atypical anorexia nervosa are as likely as underweight patients to suffer from bradycardia, or slow heart rate, a key sign of medical instability that can lead to irregular heartbeats and other complications.
These patients may also carry a heavier psychological burden than those who are underweight, due to greater concerns about food avoidance and more negative feelings about body shape and weight.
According to the DSM-5, atypical anorexia nervosa meets the criteria for anorexia nervosa. Characteristics include food restriction leading to weight loss, intense fear of gaining weight, and “alteration in the way weight or body shape is experienced.”
The only exception is that the weight of the patient with the atypical variant is within or above the normal range, despite significant weight loss.
In the study, the average BMI for the typical group at its highest was 20.7, at the low end of the healthy range, and 25.2 for the atypical group, at the low end of the overweight range. By the time they were admitted to the hospital, the average BMI of the typical group was 15.7 and the average BMI of the atypical group was 19.4.
The study found that female atypical patients were as likely as their low-weight counterparts to stop menstruating, a hallmark of hormonal suppression due to poor nutrition that affects fertility and bone density.
Both typical and atypical patients were susceptible to electrolyte imbalances from inadequate intake of sodium, potassium, calcium, and chloride, which can affect brain, muscle, and heart function.
Patients in the atypical group scored significantly higher on a questionnaire assessing eating disorder psychopathology, which addressed issues such as avoidance of food and eating, preoccupation with calories and secret eating, feelings of fatness, and discomfort when seeing the body, dissatisfaction with weight and reaction to being weighed.
The overall score for the atypical group reached 3.8, compared to 3 for the typical group. For context, the scores in women in the community are less than 1.
“One possibility for the more extreme eating disorder behaviors and cognitions among the atypical group is that some of the patients were overweight and may have experienced stigma or teasing that made them feel worse about their size,” Garber said.
“Or, if they were genetically predisposed to be on the heavier side, they might have had to employ harsher behaviors or have more severely disordered thoughts to fight their biology.”
“These findings show that atypical anorexia nervosa is a real disease, not just a minor form of ‘pre-anorexia nervosa,’” Garber added.
“Pediatricians and other primary care providers should monitor patients with large or rapid weight loss, even if they were heavier to begin with and now appear ‘normal.’ “These patients are just as sick as those diagnosed with traditional anorexia nervosa.”
Bibliographic reference:
Garber, AK, Cheng, J., Accurso, EC, Adams, SH, Buckelew, SM, Kapphahn, CJ, … Golden, NH (2019). Weight Loss and Illness Severity in Adolescents With Atypical Anorexia Nervosa. Pediatrics. https://doi.org/
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