Reasons for admission and variance of body weight at referral in female inpatients with anorexia nervosa in Germany

Abstract

Background Body mass index (BMI) at hospital admission in patients with anorexia nervosa (AN) represents a prognostic marker for mortality, chronicity and future body weight. The current study focused on the associations between BMI standard deviation score (BMI-SDS) at admission and reasons for seeking inpatient treatment. Further interest was given to the relationship between premorbid weight and weight at admission, as well as the effect of both weight at referral and reasons for admission on treatment outcome. Methods Data ascertained in the German Register of Children and Adolescents with AN were analysed to assess the parental and patient overlap for 23 predefined reasons for admission, using factor analyses and regressions models. Results Complete parent-patient data sets were available for 360 patients out of 769. The highest consensus rates between parents and patients were obtained for weight and eating behavior related reasons and hyperactivity. Based on factor analysis, four factors emerged. Premorbid BMI-SDS, age and ‘low body weight’ as stated by patients or parents explained almost 40% of the variance of the BMI-SDS at admission. Conclusions Results underscore the relevance of age and premorbid BMI for BMI at admission. Only single reasons for admission explained further variance, with ‘low body weight’ having the largest effect. Approximately 40% of the variance of BMI-SDS was explained. For the first time, the effect of premorbid BMI for BMI at admission was robustly demonstrated in a multicenter study. Of the variance in BMI-SDS at discharge, our model could explain 37%, with reasons for admission having a small effect. Further investigation of the reasons for admission would be worthwhile to improve treatment and prognosis.

Premorbid body weight predicts weight loss in both anorexia nervosa and atypical anorexia nervosa: Further support for a single underlying disorder

“…Accordingly, our current study extends our previous registry based studies (Engelhardt et al, 2020;Peters, Kolar, et al, 2021) (Garber et al, 2019;Matthews et al, 2024;Peebles et al, 2010;Whitelaw et al, 2014), the diagnostic weight cutoff should result in patients with a high premorbid BMI being less likely diagnosed with AN. In contrast, weight loss in patients with a low premorbid BMI would more likely result in their being below the weight cutoff resulting in a diagnosis of AN.…”

Differentiating anorexia nervosa and atypical anorexia nervosa with absolute weight cut‐offs results in a skewed distribution for premorbid weight among youth

“…Patients with higher BMIs face disparities in eating disorder care (e.g., Harrop et al, 2021) due to misconceptions of being less 'sick' than clinically 'underweight' counterparts with AN (e.g., Cunning & Rancourt, 2023;Eiring et al, 2021;Kons et al, 2024;Veillette et al, 2018). Given significant associations between premorbid BMI and weight loss in ours and prior samples of youth with AN and atypical AN (Coners et al, 1999;Föcker et al, 2015;Hebebrand et al, 2024;Peters et al, 2021), coupled with overlapping characteristics and sequelae in both illnesses (Billman Miller et al, 2024;Garber et al, 2019;Sawyer et al, 2016;Zanna et al, 2021), we propose that differentiating diagnoses with clinical 'underweight'-in the absence of empirical support-inadvertently reinforces widespread weightbiased stereotypes about restrictive eating disorders.…”

“…In contrast, youth with atypical AN demonstrate a greater prevalence of premorbid 'overweight/obesity' (i.e., BMI% ≥ 85th) (Lin et al, 2023;Matthews et al, 2023;Walsh et al, 2023). However, burgeoning research suggests that even in terms of weightrelated aspects, AN and atypical AN do not differ, with similar weight loss across diagnoses and an underlying regulatory mechanism in which premorbid BMI is associated with presenting weight (Coners et al, 1999;Föcker et al, 2015;Hebebrand et al, 2024;Peters et al, 2021). For example, prior studies demonstrate significant correlations between premorbid BMI and presenting BMI and premorbid BMI and weight loss in hospitalized youth with restrictive eating disorders (Coners et al, 1999;Föcker et al, 2015;Peters et al, 2021).…”

“…However, burgeoning research suggests that even in terms of weightrelated aspects, AN and atypical AN do not differ, with similar weight loss across diagnoses and an underlying regulatory mechanism in which premorbid BMI is associated with presenting weight (Coners et al, 1999;Föcker et al, 2015;Hebebrand et al, 2024;Peters et al, 2021). For example, prior studies demonstrate significant correlations between premorbid BMI and presenting BMI and premorbid BMI and weight loss in hospitalized youth with restrictive eating disorders (Coners et al, 1999;Föcker et al, 2015;Peters et al, 2021). In their parallel study, Hebebrand et al (2024) found that premorbid BMI z-scores (BMIz) predicted admission BMIz and to a larger extent, total weight loss among hospitalized youth with AN and atypical AN.…”

Childhood body mass index and the subsequent risk of anorexia nervosa and bulimia nervosa among women: A large Danish population‐based study

“…The relationship between premorbid body composition and AN might be, at least partially, explained by the underweight (BMI < 18.5 kg/m 2 or a BMI < 5th age and sex adjusted BMI‐centile) requirement for the diagnosis of AN (American Psychiatric Association, 2013). BMI at referral is positively correlated with premorbid BMI (Coners et al, 1999; Focker et al, 2015; Peters et al, 2021) and thus, an inherently lean individual is more likely to fulfill the weight criterion required for the diagnosis of AN after a weight loss compared to an individual with a higher premorbid BMI. Further, an individual fulfilling the weight criterion for AN does not qualify for a BN diagnosis, which could explain the higher BMI observed in women with BN.…”