(PS7-21) Differential Item Functioning of the Eating Disorder Diagnostic Scale Across Cisgender and Transgender or Gender Diverse Individuals

Individuals who identify as transgender or gender diverse (TGD) do not identify with, and often express their gender differently from, their gender assigned at birth. TGD individuals have elevated rates of eating disorder (ED) symptoms. However, rates of ED symptoms in TGD populations may be inaccurately estimated because most diagnostic tools were developed in cisgender populations and may encounter response bias when assessing symptoms for TGD individuals. It is, therefore, important to test for differential item functioning (DIF) of ED symptoms in TGD groups. The Eating Disorder Diagnostic Scale (EDDS) is a 23-item self-report measure developed to assess symptoms of DSM-5 EDs. Although the EDDS has shown evidence for good psychometric properties in cisgender men and women, it is uncertain if TGD individuals may respond differently to EDDS items compared to their cisgender counterparts who have the same level of ED pathology, resulting in DIF. Considering the wide use of the EDDS in clinical and research settings, gender bias in TGD populations could adversely affect detection and referral to evidence-based care, and result in inaccurate estimates of prevalence.

To address these issues, we aimed to understand whether the EDDS had evidence for item bias across college students who identified as cisgender men (n=1378), cisgender women (n=4143), and TGD individuals (n=392). Participants reported their gender identity and completed the EDDS via an online survey. We hypothesized that TGD individuals would have higher endorsement levels of EDDS items pertaining to weight concerns, fasting, and impairment in social or occupational functioning in comparison with cisgender individuals who had the same latent level of ED pathology. DIF was tested using likelihood ratio tests.

Results demonstrated that TGD individuals were less likely to endorse items assessing weight concerns than their cisgender counterparts who had the same latent ED pathology. TGD individuals had higher endorsement of some binge eating symptoms than cisgender women, but lower endorsement than cisgender men at the same level of latent ED symptoms. Only one item (eating much more rapidly than normal) showed non-uniform DIF, such that at lower levels of latent ED symptoms, TGD individuals were more likely to endorse this item, but cisgender men were more likely to endorse it at higher levels. Other EDDS items did not show evidence of DIF between gender groups.

Overall, our results indicated response bias to items assessing weight concerns and select binge eating symptoms across all genders. This study was the first to investigate item bias in ED symptoms for TGD individuals. Our findings demonstrate the need for an unbiased ED diagnostic measure to effectively assess these symptoms in TGD individuals. Providers using the EDDS may use additional measures or their clinical expertise to support their assessment of the severity of their TGD clients’ weight concerns and binge eating symptoms.