IS DIABETES REALLY A CORONARY HEART DISEASE RISK EQUIVALENT?


Nathan D. Wong, Ph.D., University of California, Irvine, CA, USA

Type 2 diabetes (T2DM) is associated with substantial increases in morbidity and mortality from coronary heart disease (CHD) and has been considered a CHD risk equivalent by the US National Cholesterol Education Program. The East-West Study originally showed persons with diabetes but no prior myocardial infarction had a similar risk of future CHD events as those with a prior myocardial infarction and no diabetes. However, recently meta-analyses note those with T2DM are at only about half the risk for CHD events as those with a known myocardial infarction. Moreover, global risk assessment shows one-half of females and one-third of males with T2DM to be a low to intermediate risk. In fact, there is a ten-fold variation in risk (0.4% to 4% annually) of CHD events according to the extent of subclinical atherosclerosis as evidenced by coronary artery calcium; the one-third of those with diabetes who do not have coronary calcium have CHD risks as low as many without diabetes or metabolic syndrome; conversely, those with coronary calcium scores of 400 or greater are at 10-fold greater risk for CHD events. These data support the role of global risk assessment and screening for subclinical atherosclerosis (eg, using coronary calcium screening) in those with T2DM.