Although blacks generally have higher glycated hemoglobin levels than whites at the same blood glucose levels, they develop retinopathy at lower HbA1c levels than whites, an Annals of Internal Medicine study finds. The authors say this difference in retinopathy risk argues against setting higher diagnostic levels of HbA1c for blacks.
Researchers examined U.S. NHANES data on over 3000 people. They found that after adjustment for such factors as hypertension and BMI, higher risks for retinopathy started at HbA1c levels of 6.0% and higher in whites, but at levels of 5.5% and higher in blacks. The reasons underlying the risk difference are unknown.
The authors conclude that their results “suggest that the HbA1c levels at which the risk for prevalent retinopathy begins to increase are lower in black adults than in white adults, arguing against a higher HbA1c diagnostic cutoff for blacks.”