Psychological research in eating disorders/disordered eating in type 1 diabetes: A systematic review using the <scp>NIH</scp> stage model for behavioural intervention development

AIMS: Eating disorders in type 1 diabetes are 2.4 times more likely to develop than those who do not have diabetes. The aim was to conduct a systematic review on psychological interventions in IRDEB (insulin-related disordered eating behaviour)/eating disorders with adults who have type 1 diabetes. The review describes the type and quality of studies with control/comparison groups, as well as qualitative research, and synthesises the research according to the NIH Stage Model of Behavioural Intervention Development. Classification according to the Model allows for discussion of gaps and recommendations for further research. METHODS: The methodology for this research followed PRISMA guidelines, with inclusion criteria of: (1) type 1 diabetes; (2) adults (age ≥18); (3) behavioural and psychological interventions in eating disorders or disordered eating; (4) primary outcome being psychological, (5) conducted from 2014 to February 2024; (6) in English; (7) full-text, peer-reviewed articles; AND (8) quantitative trials with control or comparison groups OR (9) qualitative research. RESULTS: From a total of 28 studies related to type 1 diabetes and psychological outcomes, nine studies were found to be relevant to IRDEB and eating disorders. Although studies of disorders have risen in publication, there was only one completed full RCT since 2014, which met the inclusion criteria, the Diabetes Body Project. Methodological designs for the nine studies included six qualitative studies and three experimental studies. Six studies were categorised as Stage 0, one as Stage 1, one as Stage II and one as Stage III. Two studies included participants with 'diabulimia' alone, and the seven remaining studies combined eating disorders and eating disorder symptoms (e.g., 'diabulimia', anorexia, binge-eating, bulimia). CONCLUSIONS: With the limited research that is available, and only one recently completed RCT, the opportunities for research in IRDEB/eating disorders are capacious. There is a need to tailor existing eating disorder interventions to T1D and to continue to investigate the efficacy (Stages II and III), and effectiveness (Stages IV and V), keeping in mind the unique needs and conditions under which IRDEB and eating disorder symptoms emerge.