Posted on Aug 22, 2011, 6 a.m.
Measuring glycated Hemoglobin (hemoglobin A1c) improves the ability to predict cardiovascular events in at-risk populations.
A measurement of a person’s average plasma glucose concentration over an extended period of time, glycated Hemoglobin (hemoglobin A1c [HbA1c]) is considered a marker of metabolic dysfunction and diabetes. Nina P. Paynter, from Brigham and Women's Hospital (Massachusetts, USA), and colleagues analyzed data on 24,674 women (685 of whom had diabetes) who participated in the Women's Health Study (WHS) and 11,280 men (563 with diabetes) from the Physicians' Health Study (PHS). The WHS participants had a median follow-up of 10.2 years, and the PHS participants had a median follow-up of 11.8 years. During follow-up in the WHS, 125 cardiovascular events occurred in the women with diabetes and 666 in those who did not have the disease. In the PHS the 563 men with diabetes had 170 cardiovascular events versus 1,382 in the nondiabetic men. The team analyzed the effect of adding HbA1c to the 10-year risk estimates of the National Cholesterol Education Program for Adults (ATP III) and the Reynolds Risk Score (RRS), which includes C-reactive protein and parental history of premature myocardial infarction, amnd found that = models that included HbA1c significantly improved discriminatory among diabetic participants in the WHS. Including HbA1c levels had a more modest impact among diabetic men in the PHS but still yielded a significant improvement in discriminatory power in the ATP III model. As well, HbA1c levels also improved prediction as compared with a dichotomous term for diabetes (versus a risk equivalent) in women but not in men. The team concludes that: “In both women and men with diabetes at baseline, we observed significant improvements in predictive ability of CVD risk using models incorporating HbA1c levels compared with classification of diabetes as a cardiovascular risk equivalent.”
Nina P. Paynter; Norman A. Mazer; Aruna D. Pradhan; J. Michael Gaziano; Paul M. Ridker; Nancy R. Cook. “Cardiovascular Risk Prediction in Diabetic Men and Women Using Hemoglobin A1c vs Diabetes as a High-Risk Equivalent.” Arch Intern Med, July 2011.