To be considered, an applicant with a GED would need to demonstrate exceptional academic achievement and compelling reasons for not completing a traditional high school education, along with an incredibly strong application in all other areas (extracurriculars, essays, recommendations, standardized test scores, etc.). Essentially, they would need to stand out in ways that compensate for the unconventional path.
In short, while technically possible, it's not a realistic expectation. Focusing on alternative pathways to a traditional high school diploma, such as homeschooling or a high school equivalency program that provides more structured learning and transcript opportunities, would significantly increase the chances of gaining admission to a highly selective university like Duke.