The relationship between premorbid body weight and weight at referral, at discharge and at 1-year follow-up in anorexia nervosa

Abstract

Body mass index (BMI) is one of the most important outcome predictors in patients with anorexia nervosa (AN). A low premorbid BMI percentile calculated by the patients recalled premorbid weight and the height at first admission has been found to predict the BMI at first inpatient admission. In this study, we sought to confirm this relationship. We additionally analyze the relationship between premorbid BMI percentile and BMI percentile at discharge from the first inpatient treatment and at 1-year follow-up or alternatively if applicable upon readmission within this time period. We included 161 female patients aged 11-18 years of the multisite ANDI-trial with a DSM-IV diagnosis of AN. We used a multivariate statistical model including the independent variables age, duration of illness, duration of treatment, BMI at admission and BMI percentile at discharge. The relationship between premorbid BMI percentile and BMI at admission was solidly confirmed. In addition to premorbid BMI percentile, BMI at admission and age were significant predictors of BMI percentile at discharge. BMI percentile at discharge significantly predicted BMI percentile at 1-year follow-up. An additional analysis that merely included variables available upon referral revealed that premorbid BMI percentile predicts the 1-year follow-up BMI percentile. Further studies are required to identify the underlying biological mechanisms and to address the respective treatment strategies for AN patients with a low or high premorbid BMI percentile.

Family-based intervention in adolescent restrictive eating disorders: early treatment response and low weight suppression is associated with favourable one-year outcome

“…Canalization implies a genetically determined buffering against temporary perturbations, which sustains development along a predetermined trajectory. The BMI trajectory of healthy adolescents [ 45 ] would be an example of such canalization and there is also evidence of such canalization in adolescents with AN [ 46 ]. In restrictive ED return of menstruations [ 47 , 48 ] and resumption of linear growth [ 49 ] are associated with a return to the premorbid growth trajectory.…”

ESCAP Expert Paper: New developments in the diagnosis and treatment of adolescent anorexia nervosa—a European perspective

“…In short, an increase in BMI to the 25th age-adjusted percentile and weight maintenance thereafter are indispensable preconditions for the resumption of menses [ 8 ]. Note, however, that premorbid BMI and the weight at which menstruation ceased are also important in determining target weight because there is some evidence from our and from an Italian study that patients with a higher premorbid BMI will only menstruate at a BMI nearer to their original body weight [ 58 , 61 , 62 ]. Younger patients and patients with premenarchal onset of AN are at a particular risk for protracted amenorrhea [ 58 , 63 ].…”

Influence of premorbid BMI on clinical characteristics at presentation of adolescent girls with eating disorders

“…This has also been observed in adolescents with restrictive ED not otherwise specified (EDNOS) for whom growth charts from the school health services could be used to document premorbid weight and height [ 6 ]. Adolescents with restrictive ED who start their weight loss from an overweight may have a long duration of ED symptoms but nevertheless present with higher BMI than those with a premorbid weight in the average range [ 7 – 10 ]. Despite considerable weight loss they do not reach the weight criterion for AN but fall into the EDNOS category.…”