Differences in medication adherence do not fully explain why African Americans fare more poorly than whites in managing their diabetes, a new study suggests.

Research has shown that black adults with type 2 diabetes tend to have more problems with blood sugar control, as well as a higher risk of diabetes complications, than their white counterparts. There is also evidence that African Americans are less likely to comply with their medication regimens.

To see whether this difference might contribute to racial disparities in diabetes control, researchers at Harvard Medical School in Boston reviewed the medical records of 1,806 adult patients in their health system with type 2 diabetes.

In general, the study found that black patients had a higher average blood sugar level than white patients did one year after starting drug therapy. They were also somewhat less likely to comply with their medication regimen, which was gauged by how often the patients refilled their prescriptions.

This did not, however, fully explain black patients’ poorer blood sugar control, the researchers report in the journal Diabetes Care.

Exactly what does explain the racial gap remains an open question, according to the researchers, led by Dr. Alyce S. Adams.

One possibility, they suggest, is that African Americans tend to have more severe diabetes by the time they are diagnosed and treated. So they may need more intensive treatment off the bat, including higher medication doses.

Whatever the reasons for the racial disparities, the researchers conclude, it is unlikely that improving black patients’ medication adherence will be enough to close the race gap.

More research is needed to examine possible environmental and genetic factors that may contribute to the problem of blood glucose control among African Americans with diabetes.

SOURCE: Diabetes Care, May 2008.