 | Healthy Heart | | |
Debunking the 50-50 Heart Disease Myth
October 7, 2003
Last reviewed August 13, 2008  By Thomas H. Lee, M.D.
Brigham and Women's Hospital You don't get enough good news, and, in all likelihood, you recently missed some very important reassurance that should dampen fears of heart disease for hundreds of millions of people worldwide — and sharpen efforts toward risk reduction for many others. Recently, three important studies took direct aim — and scored direct hits — on one of the most common misconceptions in medicine: the 50-50 heart-disease myth. According to this myth, only about half of people who develop heart disease have any of the four major traditional "risk factors" — smoking, diabetes, hypertension or high cholesterol. This myth is often quoted, and, if it were true, would have a frightening implication: Any of us, anytime, could be suddenly stricken down by a heart attack. For a generation of aging baby boomers, the logical next step is a search for further information that might provide reassurance that this is not going to happen to me! The kind of "next steps" that many people are taking include getting electron-beam CT scans of the heart, exercise tests and echocardiograms and blood tests — all in search of that "clean bill of health." These tests are expensive, and rarely give that complete reassurance that is desired. In fact, they often lead to sleepless nights and even more tests. On August 20, 2003, the Journal of the American Medical Association published two separate studies that briefly analyzed long-term data on several hundred thousand people, and found that 80% to 90% of people who developed heart disease, and more than 95% of patients who died of heart disease, had at least one of the four major cardiac risk factors. In other words, of people who "drop dead" from a heart attack, fewer than one out of 20 had no warning because they had none of these four risk factors. So if you do not smoke, do not have diabetes, have normal blood pressure, and your lipid levels are not at high-risk levels, your heart disease risk is really quite low. A third study in the same issue analyzed available information on C-reactive protein (CRP), which is a blood test that many experts hope will greatly improve our ability to predict who is at high risk of heart attacks. This study concluded that it is not at all clear that CRP adds much information on risk after knowledge of all four major risk factors is taken into account. This perspective may be surprising, since other experts have been so excited about the potential of CRP. The reason they have been excited is another 50-50 rule which happens to be true — half of heart attacks occur to people with normal cholesterol levels. The new research just published means that most of the people who have heart attacks with normal cholesterol happen to have hypertension, diabetes or histories of cigarette smoking. While these new findings should provide reassurance to the many people without any of the four risk factors, they should shift attention by others from "risk measurement" to "risk reduction." In short, we probably give too much energy to trying to measure our risk of heart disease these days, and not enough to actually lowering it through the hard work of weight loss, exercise and other lifestyle changes, along with careful monitoring of our chronic diseases if we have them. The debunking of the 50-50 myth about risk factors should mean a call to action for some, and a good night's sleep for others. Thomas H. Lee, M.D. is the chief executive officer for Partners Community HealthCare Inc. He is a professor of medicine at Harvard Medical School. He is an internist and cardiologist at Brigham and Women's Hospital. Dr. Lee is the chairman of the Cardiovascular Measurement Assessment Panel of the National Committee for Quality Assurance.
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