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Threshold for diabetes diagnoses may need to be lower for black people

Category: Diabetes

A blood test to measure hemoglobin A1C (HbA1c) levels is a good indicator of an individual's blood sugar control during the previous two to three months. However, whether these test results are indicative of diabetes may be unclear when it comes to physiological differences between white and black patients, according to researchers from Beth Israel Deaconess Medical Center.

Previous studies suggested that black individuals usually have higher HbA1c levels compared to white people, despite the fact that the actual levels of blood sugar tend to be similar. In order to investigate whether this disparity had an impact on the development of retinopathy, a team of scientists conducted an experiment that included subjects from both racial groups. The researchers expected retinopathy to be delayed in black study participants.

"Our study results show that the risk of diabetic retinopathy is higher for blacks at any given hemoglobin A1C level between 5 percent and 7 percent, and that the higher risk at a hemoglobin A1C level of 5.5 to 5.9 percent for blacks was comparable to the risk at a hemoglobin A1C level of 6.0 to 6.4 percent for whites," said researcher Yusuke Tsugawa, M.D., M.P.H.

If supported by further research, these results suggest that the diagnostic threshold for diabetes should be lower for black patients, and that people in this group may benefit from early screens for retinopathy.

In the meantime, doctors can help patients interpret a blood test of HbA1c levels.