Socioeconomic and clinical factors associated with genetic testing completion in Stargardt disease.

PURPOSE: Genetic testing (GT) is crucial for Stargardt disease (STGD) diagnosis and clinical trial (CT) eligibility; however, predictors of GT completion remain understudied. We identified factors associated with GT completion and characterized CT participation among genetically confirmed patients. METHODS: We retrospectively reviewed 280 patients with clinically diagnosed STGD who were evaluated at a US tertiary referral center (2003-2024). Multivariable logistic regression was used to identify predictors of GT completion. RESULTS: Among 280 participants, 246 (88%) completed GT. GT completion was significantly less likely in participants who were Black (odds ratio [OR]: 0.40, 95% CI: 0.16-0.98), under/uninsured (OR: 0.47, 95% CI: 0.19-0.97), without genetic counseling (GC) (OR: 0.09, 95% CI: 0.03-0.22), or without reproductive plans (OR: 0.35, 95% CI: 0.14-0.89). Clinical factors (eg, age of onset, visual acuity, and family history) showed no significant associations. Common reasons for noncompletion included loss to follow-up (41%), patient refusal (26%), and awaiting GC (24%). Among 223 ABCA4-positive participants, 45 (20%) enrolled in CTs, with most (91%) completing GC. CONCLUSION: Despite high overall GT completion rates, significant racial and socioeconomic disparities exist. GC emerged as the strongest modifiable factor, conferring over 10-fold higher odds of GT completion. Socioeconomic barriers drive testing disparities in STGD, rather than disease severity or clinical characteristics.