BOSTON Healthcare providers should take into account differences among racial groups when using hemoglobin A1C levels to diagnose and monitor diabetes, new research from Beth Israel Deaconess Medical Center suggests.
In a study published Aug. 7 in the Annals of Internal Medicine, researchers analyzed National Health and Nutrition Survey data from 2005 to 2008 to examine the association between hemoglobin A1C levels in black and white adults and the risk for retinopathy, an eye complication of diabetes that is detectable early in the disease and can ultimately lead to blindness.
"There have been several studies indicating that hemoglobin A1C levels are consistently higher in blacks than in whites, even though underlying blood sugar levels are similar," said lead author Yusuke Tsugawa, MD, MPH, a primary care fellow at Beth Israel Deaconess Medical Center. "We looked at the data to determine if a higher diagnostic cutoff of A1C level should be used to diagnose diabetes in blacks than in whites, or if there should be a single cutoff for all races."
Diabetes has been historically diagnosed based on blood glucose tests, but in 2010 the International Expert Committee recommended adding hemoglobin A1C because it is a more reliable test that reflects average blood sugar over the past two to three months.
In line with the Expert Committee's recommendation, the World Health Organization and the American Diabetes Association subsequently adopted a hemoglobin A1C level of 6.5 percent or higher as a new diagnostic criterion for diabetes. For people who do not have diabetes, a normal hemoglobin A1C level is around 5 percent.
Given the evidence of naturally higher A1C levels in black people, the researchers expected to also find a delayed development of retinopathy in blacks compared to whites. Instead, the data showed that the A1C level where the risk of retinopathy begins to increase was paradoxically lower in black p
|Contact: Kelly Lawman|
Beth Israel Deaconess Medical Center