HbA1c Measurements Predict Heart Disease in Diabetics

The glycosalated HbA1c test reflects the average blood glucose level over the previous 8 to 13 weeks and is generally viewed as an indicator on how well the patient is managing or controlling their diabetes.

A team of scientists at Brigham and Women's Hospital (Boston, MA, USA) set out to determine how useful monitoring HbA1c levels might be in predicting cardiovascular events. They gathered data from 24,674 females, of whom 685 had had diabetes at baseline, while out of 11,280 males 563 had diabetes at baseline. Baseline blood samples were evaluated for HbA1c, C-reactive protein, and cholesterol levels. The females were followed up for new CVD incidents for an average of 10.2 years, and the males for 11.8 years.

The results of the study showed that within the female cohort, there were 125 cardiovascular events out of 685 diabetic participants, compared to 665 out of 24,674 without diabetes. For the male diabetic cohort there were 170 cardiovascular events out of 563 participants, compared to 1,382 out of 11,280 without diabetes. The scientists noted that including HbA1c modeling for CVD improved CVD prediction compared to the general prediction of all high-risk diabetes participants. This was especially the case among females. The risk modeling showed that 71.9% of women with diabetes in this study had a less than 20% risk of CVD over a ten-year period, compared to just 24.5% of their male counterparts.

The study concluded that in these large population-based cohorts of both men and women, presence of diabetes alone did not confer a 10-year risk of CVD higher than 20%, and measurement of HbA1c level in diabetic subjects improved risk prediction compared with classification as cardiovascular risk equivalent. The study was published on July 25, 2011, in the Archives of Internal Medicine.

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