The American Heart Association says more than 1 million Americans are hospitalized for heart attacks every year, and nearly half die.
Heart disease is the leading cause of death in the United States.
But in an eight-state study of hospital discharge data, Dr. John Westfall and a colleague at the University of Colorado Health Sciences Center found 10 percent to 15 percent of heart attack incidents might have been counted twice because of the increasingly common practice of transferring patients between hospitals. If that rate of overcounting is the same nationwide, then the true number of U.S. heart attacks each year is 800,000 or 900,000, Westfall said. The double-counting is especially a problem in rural areas, where heart attack patients often are transferred to large urban hospitals for specialized care. If double-counting drives the heart attack numbers up while the number of heart attack deaths remains roughly constant, then the mortality rate appears to drop, he said. There are about 100,000 or 200,000 fewer heart attacks per year.