A new study from researchers at Boston’s multispecialty medical group Harvard Vanguard Medical Associates has found that black patients with diabetes tend to receive worse medical care than white patients with the disease, even if they visit the same doctor.

“Amongst all providers, black patients received lower-quality care, even if white patients went to the same doctors,” says study author Thomas D. Sequist, MD, a primary-care physician at Harvard Vanguard.

The study, published in the June 9 issue of the Archives of Internal Medicine, examined 90 primary-care physicians who cared for black and white adult patients with type 2 diabetes. According to the researchers, the study results suggest that racial disparities in diabetes care are the result of deeper, systemic issues, not just differences in individual doctor care.

Dr. Sequist says that the effectiveness of counseling on black patients and their ability to afford medications are two factors that might play a role in the disparities. More research needs to be conducted, however, to determine the exact causes, suggests Sequist.