The AN-PLUS Phenotype: Admission Percent Treatment Goal Weight Trajectories and Clinical Complexity in Adolescents

AI Summary

13.6% of hospitalised adolescents with anorexia nervosa met the AN-PLUS phenotype characterised by nonresponse to FBT and severe hospital utilisation.
Declining admission %TGW group had younger symptom onset and greater clinical complexity, including restraints, constant observation, involuntary admissions, code white events, and family ED history.
Declining admission %TGW flags a high complexity subgroup amenable to earlier identification and individualised care pathways.

TL;DR (AI Generated)

Two trajectory groups were identified: declining admission %TGW (DAT; n = 14) versus stable/increasing admission %TGW (n = 53).

DAT had younger symptom onset: 11.9 (1.59) versus 13.1 (1.7) years (p <.017) and greater complexity, based on indicators present during any hospitalization over the study period, including constant observation(p <.011), physical restraints(p <.002), chemical restraints(p <.004), hospital safety alerts for violent, aggressive, or otherwise unsafe behavior ("code white" events) (p <.042), involuntary admissions(p <.029), and family history of ED (p <.042).

Weekly weight gain was similar at first hospitalization in the DAT and stable/increasing admission %TGW groups (1.3 vs. 1.2 kg/week; p =.68) but increased only in the DAT group by an additional.52 kg/week at each subsequent hospitalization (p =.0125).

Basic summary

J Adolesc Health. 2026 Sep 22:S1054-139X(26)00370-8. doi: 10.1016/j.jadohealth.2026.08.029. Online ahead of print.

ABSTRACT

PURPOSE: A subset of adolescents with anorexia nervosa (AN) have severe, treatment-nonresponsive illness with repeated/prolonged hospitalizations. Our group introduced the AN-PLUS construct (poor quality of life, lack of response to first-line treatment, medically severe and unstable, and severe symptomatology) to call attention to this at-risk subset of patients with AN. This study aimed to identify youth with high inpatient utilization and family-based treatment (FBT)-nonresponsive AN and characterize the proposed AN-PLUS phenotype.

METHODS: Retrospective chart review at SickKids (Toronto) identified youth aged 10-18 years with a primary diagnosis of AN using International Classification of Diseases, 10th Revision, Canada F50 codes in the Discharge Abstract Database from 2018 to 2023. Severe AN was defined as nonresponse to family-based treatment and either at least two hospitalizations within 6 months or one hospitalization lasting more than 4 months. Groups were categorized by longitudinal admission percent treatment goal weight (%TGW) trajectories.

RESULTS: Of 491 adolescents with AN, 67 (13.6%) met the inclusion criteria. Two trajectory groups were identified: declining admission %TGW (DAT; n = 14) versus stable/increasing admission %TGW (n = 53). DAT had younger symptom onset: 11.9 (1.59) versus 13.1 (1.7) years (p < .017) and greater complexity, based on indicators present during any hospitalization over the study period, including constant observation(p < .011), physical restraints(p < .002), chemical restraints(p < .004), hospital safety alerts for violent, aggressive, or otherwise unsafe behavior (“code white” events) (p < .042), involuntary admissions(p < .029), and family history of ED (p < .042). Weekly weight gain was similar at first hospitalization in the DAT and stable/increasing admission %TGW groups (1.3 vs. 1.2 kg/week; p = .68) but increased only in the DAT group by an additional .52 kg/week at each subsequent hospitalization (p = .0125).

DISCUSSION: Overall, 13.6% of hospitalized adolescents with AN met AN-PLUS phenotype. Declining admission %TGW marked a high-complexity subgroup whose earlier identification could enable individualized care pathways.

PMID:42954962 | DOI:10.1016/j.jadohealth.2026.08.029

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