A non-fasting blood sugar test thought to help predict heart and stroke risks didn’t hold up in a large analysis of studies.
The non-fasting blood test indicates blood sugar control by averaging levels over about three months.
It was hoped that adding the test, called glycated hemoglobin or HbA1c, to standard heart disease risk factors like smoking, age and cholesterol levels would improve doctors' ability to predict who will develop cardiovascular disease, researchers say.
In 2012, the Canadian Cardiovascular Society suggested measuring fasting glucose, HbA1C or both might help with those predictions. Doctors use risk prediction categories when making decisions about sending patients for more evaluation, such as an exercise stress test or prescribing preventive drugs.
Now an analysis of data from 73 studies on nearly 295,000 adults without a history of diabetes or cardiovascular disease (CVD) questions the value of incorporating the non-fasting blood sugar test. Measuring HbA1c wasn’t associated with "clinically meaningful improvement" in assessing heart and stroke risks.
"In adults without a known history of diabetes or cardiovascular disease, adding HbA1c to conventional CVD risk factors was associated with little improvement in the prediction of CVD risk," Dr. Emanuele Di Angelantonio of the University of Cambridge in the U.K. and his co-authors concluded in Wednesday’s issue of the Journal of the American Medical Association.
The participants were mainly from North America or Europe. Their average age was 58 when the study began. At the nine year half-way point of the followup, there were 20,840 fatal and nonfatal cardiovascular events such as heart attacks and strokes.
Incorporating other measures of blood sugar, such as fasting, also didn’t help the predictions.
The study was funded by the British Heart Foundation, the U.K. Medical Research Council, U.K. National Institute of Health Research, and the Cambridge Biomedical Research Centre.