Is the heart attack going out of style?
Hospitalization rates for heart attacks are going down in the U.S. This may be the result of prevention efforts. Two studies published in 2010 show that the American heart attack rate is continuing to decline. The main finding in the first study, published in Circulation and based on Medicare data, was that hospitalization rates for heart attack dropped by about 23% between 2002 and 2007.
The second study was based on the hospitalization records of 3 million people ages 30 and older enrolled in a particular Kaiser Permanente health plan. Again, the overall finding was the decline in hospitalizations for heart attack at 24% from 1999 to 2008.
From 1970 until 2000, hospitalizations for heart attacks and related problems like angina decreased for people less than 65 years of age but increased for people ages 65 and older between the mid-1960s till about 2000. It seems that heart disease wasn’t being so much prevented as postponed to an older age.
But the Circulation study — as well as some others — shows that since 2000, hospitalization rates for heart attacks have been going down even for people 65 and older. Why is that? Hospitalization rates for all conditions have been going down for years for many reasons, but the rate for heart attacks seems to be falling much faster.
The researchers believe there has been a true decline in the number of heart attacks and related conditions. Decades of efforts to encourage people to eat right, exercise more, and stop smoking are paying off. Also, better treatments for conditions that raise the risk of heart disease—particularly high cholesterol and high blood pressure—are contributing.
More Serious vs. Less Serious Heart Attacks
To understand rates of heart attacks, and rates of death from heart attacks, it’s important first to understand that heart attacks come in at least two “flavors.” The more severe ones are caused by a blockage of a coronary artery that results in significant damage to the heart muscle (myocardium). In the milder ones, the blockage isn’t as complete, so the tissue damaged by lack of blood isn’t as large. Doctors call the serious heart attacks STEMIs (ST-elevation myocardial infarctions). The name for milder ones is non-STEMIs.
The Kaiser data showed a 62% decrease in hospitalizations for the serious brand of heart attacks. In contrast, the number of hospitalizations for the milder type of heart attack increased through 2004. In 1998, the Kaiser data indicate that the number of serious and mild heart attacks were about the same. By 2008, there were three times as many hospitalizations for the milder heart attacks as there were for the STEMIs.
What explains this change, in just a decade? Blood tests that detect proteins released by injured heart muscle are important in diagnosing a heart attack. In the past 20 years, these blood tests have gotten better. One, called troponin, has proved to be especially useful. So the main reason that numbers of milder heart attacks are rising is that doctors have gotten better at diagnosing them.
Heart Attack Death Rates
Most heart attacks are not fatal, even the more severe type. The good news is that there’s been a steady decline in heart attack deaths in the United States since 1970. Could it be that more people are dying of heart attacks before ever reaching the hospital? Data from several studies suggest that’s not the case. Could it be that doctors are classifying heart attacks under other heart-related diagnoses for billing purposes? They checked, and hospitalization rates for conditions like unstable angina and heart failure are also going down, so it doesn’t seem “code shifting” is occurring.
There are two reasons for the declining rate of death from heart attack. Not surprisingly, a big reason is the declining rates of heart attacks and related conditions. A second reason is improved treatments for heart attacks—both the more severe type and the milder type. We appear to be in a new era of heart attack when milder cases are outnumbering the devastating “widow makers” of old, and when our treatments for both types are improving.
September 2010 update
Beating Heart Disease: Strategies for a healthy heart
If you follow the news about heart disease closely, it’s easy to be overwhelmed or confused about what puts you at risk and how you can protect yourself. This report helps you identify the risk factors you can control, which range from medical conditions such as high blood pressure to lifestyle choices such as an unhealthy diet or lack of exercise. Learn more »