Adding hemoglobin A1c level to traditional cardiovascular risk factors doesn’t improve the prediction of incident cardiovascular disease among middle-age and older adults who don’t have diabetes, according to a large analysis published online March 25 in JAMA.
Some guidelines have suggested that it may be helpful to include information on glycemia measures such as HbA1c in models that predict CVD risk, even among patients who don’t have diabetes, said Dr. Emanuele Di Angelantonio of the University of Cambridge (U.K.) and his associates in the Emerging Risk Factors Collaboration.
To determine whether or not HbA1c would improve risk assessment for CVD, they analyzed data collected for 294,998 participants in 73 prospective cohort studies conducted in 20 countries, which recorded incident cardiovascular events during a median follow-up of 10 years. None of the study subjects had diabetes; approximately 86% lived in Europe or North America, and the mean age at baseline was 58 years.
There was a J-shaped association between HbA1c and CVD risk. However, in several different statistical analyses of the data, HbA1c levels did not add to CVD risk assessment in a clinically meaningful way. HbA1c levels did nothing to help distinguish participants who developed CVD from those who did not. And adding HbA1c values to other, traditional cardiovascular risk factors did not result in reclassification of study participants from one risk category to another, the investigators said (JAMA 2014 March 25 [doi:10.1001/jama.2014.1873]).
This study was funded by the British Heart Foundation, the U.K. Medical Research Council, the U.K. National Institute of Health Research, and the Cambridge Biomedical Research Centre. Dr. Di Angelantonio reported ties to Lead-Up Medical Network, Merck, John Wiley & Sons, Elsevier, and Pfizer; his associates reported ties to numerous industry sources.