Weight history tied to illness severity in inpatients with restrictive eating disorders

Among inpatients with restrictive eating disorders, those with large, rapid or long-duration weight loss appear to have greater illness severity regardless of their current weight, a study has found.

Researchers used data from the Study of Refeeding to Optimize Inpatient Gains and looked at 66 inpatients with anorexia nervosa (AN) and 50 with atypical AN (AAN) aged 12–24 years. They calculated the difference between the highest historical percentage median body mass index (BMI) and BMI at admission to estimate the amount of weight loss.

The mean age of the cohort was 16.5 years, and the majority were women (91 percent). There was no significant difference in weight history or admission heart rate (HR) between the AN and AAN groups. However, Eating Disorder Examination Questionnaire global scores were higher in the latter (mean, 3.80 vs 3.00; p=0.02).

In multivariable regression models controlling for weight at admission, lower HR was associated with rapid weight loss (β, −0.492, 95 percent confidence interval [CI], −0.883 to −0.100; p=0.01). Furthermore, lower serum phosphorus correlated with a greater amount (β, −0.005, 95 percent CI, −0.010 to 0.000; p=0.04) and longer duration (β, −0.011, 95 percent CI, −0.017 to 0.005; p=0.001) of weight loss.

Weight and menstrual history explained 28 percent of the variance in HR and 36 percent of the variance in serum phosphorus.

The present data indicate that weight history is independently associated with markers of malnutrition in inpatients with restrictive eating disorders across a range of body weights, the researchers said. As such, weight history should be considered when evaluating illness severity on hospital admission.