Predicting Weight Gain in Hospitalized Bulimics

Most bulimic patients entering inpatient or outpatient treatment have been dieting. However, once they are hospitalized, bulimic patients lose their preferred means of weight regulation (such as dieting, binge eating, and purging). Michael R. Lowe, PhD, and colleagues at Hahnemann University and the Renfrew Foundation studied 61 bulimic inpatients to learn how hospitalization affected their body weight.

At admission, the mean body mass index (BMI) was 22.29 kg/m2. The researchers also evaluated the mean average degree of weight suppression (the difference between highest BMI ever and current BMI). During the average hospital stay of 17 days, patients gained an average of 1.6 kg, or 3.5 lb. The researchers found that the degree of weight suppression, defined in both absolute and relative terms, independently predicted weight gain during hospitalization. Thinner patients had larger weight gains, which might be explained by the fact that underweight bulimic patients were encouraged to gain weight during their hospital stay.

They then examined the relationship between weight change and change in clinical indicators. The more weight bulimic patients gained during hospitalization, the more their binge eating decreased—thus, weight gain was associated with improved clinical indicators.

The researchers found that many bulimic patients used radical weight control behaviors because of legitimate fears of becoming overweight again. The results also suggested that bulimic persons who are below normal weight for their height and/or well below their highest weight ever might benefit from partial weight restoration during treatment. Some patients with BN become overweight after treatment, but there are some specific reasons why this occurs. First, some patients have a long history or a family history of obesity that may predispose them to obesity or they may have been binge-eating and purging for so long that their body composition has changed in a way that predisposes them to fat accumulation. Dr. Lowe presented the results of the study at the Eating Disorders Research Society.