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Changes in Incidence of Heart Attacks
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What is the problem and what is known about it so far?
Heart attacks occur when the blood flow through the arteries to the heart (coronary arteries) is blocked for a time long enough to damage or kill a portion of heart muscle. Most, but not all, heart attacks cause symptoms, such as severe, crushing chest pain; nausea; shortness of breath; and a feeling of impending doom. Some people with heart attacks die immediately, before they receive medical attention. Others are admitted to hospitals and treated for their symptoms. Several things, such as a eating a healthy diet, avoiding tobacco, exercising, and taking aspirin and cholesterol-lowering medicines, may help prevent heart attacks. In addition, many treatments given after a heart attack prevent death and complications. People's lifestyles and the way doctors try to prevent and treat heart attacks have changed over time. We do not know how these changes have affected the occurrence (incidence) and outcomes of heart attacks.
Why did the researchers do this particular study?
To describe how the incidence and rates of death from heart attacks changed from 1979 to 1994.
Who was studied?
The study included the adult population of Olmsted County, Minnesota.
How was the study done?
Researchers used hospital records to identify adults who had had heart attacks between 1979 and 1994. They reviewed the therapies that were given to patients with heart attacks and noted whether patients died in the hospital. They also reviewed county records to identify patients who died within 1 month of being hospitalized for a heart attack. The researchers then looked at whether the percentages of the population that were hospitalized for heart attacks or died of heart attacks changed over time.
What did the researchers find?
Hospital records showed that 1820 heart attacks occurred in the study sample from 1979 to 1994. Several changes were noted in the 1990s compared with earlier years. First, more heart attacks were seen in older people and fewer in younger and middle-aged people. Second, the incidence of heart attacks decreased by 8% in men but increased by 36% in women. Third, survival rates improved in people younger than age 75 but did not change in people older than age 75. Finally, more patients received medicines, such as aspirin, reperfusion or “clot-buster” therapy, and β-blockers.
What were the limitations of the study?
The study only looked at patients hospitalized for heart attacks. It does not give us information about patients with heart attacks who died before hospitalization or who never went to the hospital. Also, the study is from one geographic region. The results may not apply to people in other regions who have different lifestyles and different prevention and treatment practices.
What are the implications of the study?
The incidence of heart attacks may be increasing in women and older people but decreasing in men and younger and middle-aged people. Survival rates may be improving among patients younger than 75 years of age but not among the oldest patients.
Article and Author Information
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The summary below is from the full report titled “Trends in the Incidence and Survival of Patients with Hospitalized Myocardial Infarction, Olmsted County, Minnesota, 1979 to 1994.” It is in the 5 March 2002 issue of Annals of Internal Medicine (volume 136, pages 341-348). The authors are VL Roger, SJ Jacobsen, SA Weston, TY Goraya, J Killian, GS Reeder, TE Kottke, BP Yawn, and RL Frye.
- Copyright ©2004 by the American College of Physicians
