Examining a staging model for anorexia nervosa: empirical exploration of a four stage model of severity

Sarah Maguire,Bryony Bamford,Kirsty M Fromholtz,Lois J Surgenor,Daniel Le Grange,Stephen Touyz,Hubert Lacey,Ross D Crosby,Scott G Engel

doi:10.1186/s40337-017-0155-1

Abstract

BackgroundAn illness staging model for anorexia nervosa (AN) has received increasing attention, but assessing the merits of this concept is dependent on empirically examining a model in clinical samples. Building on preliminary findings regarding the reliability and validity of the Clinician Administered Staging Instrument for Anorexia Nervosa (CASIAN), the current study explores operationalising CASIAN severity scores into stages and assesses their relationship with other clinical features.MethodIn women with DSM-IV-R AN and sub-threshold AN (all met AN criteria using DSM 5), receiver operating curve (ROC) analysis (n = 67) assessed the relationship between the sensitivity and specificity of each stage of the CASIAN. Thereafter chi-square and post-hoc adjusted residual analysis provided a preliminary assessment of the validity of the stages comparing the relationship between stage and treatment intensity and AN sub-types, and explored movement between stages after six months (Time 3) in a larger cohort (n = 171).ResultsThe CASIAN significantly distinguished between milder stages of illness (Stage 1 and 2) versus more severe stages of illness (Stages 3 and 4), and approached statistical significance in distinguishing each of the four stages from one other. CASIAN Stages were significantly associated with treatment modality and primary diagnosis, and CASIAN Stage at Time 1 was significantly associated with Stage at 6 month follow-up.ConclusionsProvisional support is provided for a staging model in AN. Larger studies with longer follow-up of cases are now needed to replicate and extend these findings and evaluate the overall utility of staging as well as optimal staging models.

Highlights

An illness staging model for anorexia nervosa (AN) has received increasing attention, but assessing the merits of this concept is dependent on empirically examining a model in clinical samples
Clinician Administered Staging Instrument for Anorexia Nervosa (CASIAN) Stages were significantly associated with treatment modality and primary diagnosis, and CASIAN Stage at Time 1 was significantly associated with Stage at 6 month follow-up
Provisional support is provided for a staging model in AN

Summary

Introduction

An illness staging model for anorexia nervosa (AN) has received increasing attention, but assessing the merits of this concept is dependent on empirically examining a model in clinical samples. The use of clinical staging as a method for operationalising severity is widespread in the medical disorders including malignancies, cardiac failure, autoimmune diseases and burns to name a few [1] (See Maguire et al, in Latzer, 2010 for review). It is a proven strategy in these disorders where both prognosis and treatment are guided by stage. Four stage models of illness severity in mental illness are the norm (for a recent systematic review see Cosci and Fava [12], where four stage models for schizophrenia, uni and bipolar depression, alcohol use and panic attacks are summarised). The field of staging has been influenced by the seminal and most successful disease staging model – the Tumour, Node, Metastatsis (TNM) for cancer, utilising a four stage model roughly equating to mild, moderate, severe and extremely severe stages

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