Associations between Disordered Eating Behaviors and HbA1c in Young People with Type 1 Diabetes: A Systematic Review and Meta-analysis

Background: In type 1 diabetes, disordered eating behaviors (DEB) can adversely impact HbA _1c. Diabetes-adapted DEB questionnaires assess intentional insulin omission, whereas generic questionnaires do not. Given the number of studies describing DEB-HbA _1c associations pub-lished over the past decade, an updated systematic review is warranted. Objective: The study aimed to examine the associations between DEBs assessed by generic and di-abetes-adapted questionnaires (and subscales) and HbA _1c among young people (<29 years) with type 1 diabetes. Methods: A systematic search was conducted in PubMed, Embase, PsycInfo, and CINAHL data-bases. Observational studies examining associations between DEB as assessed by questionnaires and HbA _1c were included. Publication information, DEB and HbA _1c characteristics, and DEB-HbA _1c associations were extracted. Hedges’ g was calculated for mean HbA _1c differences between groups with and without DEB. Results: The systematic search yielded 733 reports, of which 39 reports representing 35 unique studies met the inclusion criteria. Nineteen studies assessing DEB by diabetes-adapted questionnaires (n=5,795) and seven using generic questionnaires (n=2,162) provided data for meta-analysis. For diabetes-adapted questionnaires, DEB was associated with higher HbA _1c (g=0.62 CI=0.52; 0.73) with a similar effect size when restricted to validated questionnaires (g=0.61; CI=0.50; 0.73). DEB was not associated with HbA _1c for generic questionnaires (g=0.19; CI=-0.17; 0.55), but significantly associated with higher HbA _1c for validated generic questionnaires (g=0.32; 95% CI=0.16-0.48). Participant and HbA _1c collection characteristics were often inadequately described. Conclusion: Diabetes-adapted DEB questionnaires should be used in youth with type 1 diabetes because they capture intentional insulin omission and are more strongly associated with HbA _1c than generic DEB questionnaires.