Survival after a heart failure diagnosis has greatly improved over the past 50 years, according to a study from the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health. The study, which analyzed data from the NHLBI's landmark Framingham Heart Study (FHS), found that the risk of dying after being diagnosed with heart failure had dropped by about a third in men and women during that period.
The study, which appears in the October 31, 2002, issue of The New England Journal of Medicine, also found that new cases of heart failure had dropped by about a third for women during the same period. However, the number of new cases for men remained unchanged.
"These findings offer good news about a highly lethal disease," said NHLBI Director Dr. Claude Lenfant. "However, heart failure still affects far too many Americans and more than half of those who develop it die within 5 years of diagnosis.
"Prevention remains the best defense against heart failure. Americans can greatly reduce their chances of developing it by taking steps to prevent or control high blood pressure, heart disease, and other conditions that can lead to heart failure."
Heart failure occurs when the heart loses its ability to pump enough blood through the body. It often develops slowly, over many years.
About 4.8 million Americans have heart failure, with about 550,000 new cases being diagnosed each year. Heart failure contributes to about 287,000 deaths a year.
In the new study, researchers, led by FHS Director Dr. Daniel Levy, analyzed data on 10,317 FHS participants drawn from the original enrollees and the offspring generation, including their spouses. The study had equal numbers of men and women.
The original participants, who began enrolling in FHS in 1948, were evaluated every 2 years; the offspring generation, which began enrolling in 1971, was evaluated in 1979 and every 4 years after that. The evaluation included a physical examination, laboratory tests, and an electrocardiogram. Throughout the 50 years of data collection, FHS used the same criteria to define heart failure.
In order to assess trends, researchers divided the data into four periods: 1950-69, 1970-79, 1980-89, and 1990-99.
- From 1950 to 1999, there were 1,075 cases of heart failure?about equally divided between men and women.
- In 1950-69, 70 percent of men died within 5 years of being diagnosed with heart failure; in 1990-99, that rate dropped to 59 percent. In 1950-69, 57 percent of women died within 5 years of heart failure diagnosis; in 1990-99, that rate dropped to 45 percent.
- For women, the number of new cases dropped by a third from 1950 to 1979, with no additional change from 1980 to 1999. For men, there was no significant change in the number of new cases from 1950 to 1999.
- Deaths from heart failure decreased on average by 12 percent per decade for women and men.
"The reason that new cases are on the decrease for women but not men may have to do with a gender difference in the causes," said Levy. "Although high blood pressure and heart attack are important causes of heart failure in both men and women, uncontrolled hypertension is more prominent as a risk factor for the disease in women, while heart attack plays a greater role in men.
"Treatment for high blood pressure has improved greatly over the past 50 years and has been shown to dramatically cut the number of new cases of heart failure. This may explain why fewer women are developing the disease," he continued.
"Heart attack treatment and survival have improved since 1950 as well. But, many of those who now survive have a damaged heart, which makes them vulnerable to heart failure. A consequence of advances in the treatment of heart attack is a growing group of patients at risk for the occurrence of heart failure."
He added that it is likely that the availability of drugs and other treatments for heart failure is the key reason survival has improved in the past 50 years.
But he cautioned that, since the findings are based on one, mostly white study, more research must be done to check trends on the survival and number of new cases in other racial and ethnic groups.
To interview Levy, contact the NHLBI Communications Office at (301) 496-4236.