Target Weight Discrepancy: A Simple Prognostic Tool

In both bulimia nervosa and anorexia nervosa, patients express a morbid fear of fatness. Janelle W. Coughlin, PhD, and researchers at Johns Hopkins University, Baltimore, have found that the difference between the patient’s desired target weight (using a patient’s response to the question, “How much would you like to weigh?”) and target weight based on age, sex, and height may provide a simple and useful tool to gauge prognosis.

The researchers hypothesized that patients with greater discrepancies in target weight would have longer stays in inpatient and partial hospital services and would have greater psychopathology. As reported at the AED meeting in Orlando in May, they calculated target weight discrepancies (TWDs) among 194 patients admitted to the Johns Hopkins Eating Disorder service who had Structured Clinical Interview for DSM-IV (SCID)-diagnosed eating disorders and who were participating in an outcomes study. Comparisons were made between 63 patients with bulimia nervosa and 131 with anorexia nervosa (AN).

Discrepancies higher among AN patients

AN patients had significantly higher TWDs than did BN patients (13.5 vs. 6.6 lb). Patients who had previous admissions had higher TWDs than did those admitted for the first time (13.7 vs. 9.4 lb). The group with high TWDs scored higher on neuroticism and lower on conscientiousness, had more depressive symptoms, were less ready to change, and were more likely to engage in restricting and purging eating behaviors in the month before they were admitted for treatment. There were no differences between the groups on the Eating Disorders Inventory-2 (EDI-2), Sociocultural Attitudes Towards Appearance Questionnaire (SATAQ), or perceived coercion regarding treatment.

Calculating TWD might be a simple and effective prognostic tool. Patients with high TWD exhibit more psychopathology and problem behaviors, and are more likely to have chronic disease.