Doctors have made progress over the last five decades in keeping heart failure patients alive and preventing the life-threatening condition, at least in women, a new study shows.
While new drugs have been shown to improve survival, the research reported in Thursday's New England Journal of Medicine is the first population-based evidence that people are living longer with the disease.
About 4.8 million people have heart failure, which occurs when a weakened heart cannot pump blood efficiently through the body. It mostly afflicts the elderly and is thought to be on the rise because of the aging of the U.S. population. It contributes to about 287,200 deaths a year.
Analyzing 50 years of data from the Framingham Heart Study, the researchers found the number of new cases in women had dropped by about one-third. But there was no change for men.
They also concluded that survival improved for men and women, with the risk of dying after developing heart failure falling about one-third since the 1950s.
Despite the improvements, "we still do have to appreciate that this is a highly lethal condition," said Dr. Daniel Levy, director of the government-funded Framingham study, which has been tracking residents of the Boston suburb since 1948.
"We think it is most likely that improvements in treatment are reducing the number of people with new heart failure and prolonging survival," said Levy.
The study of 10,317 people compared death rates from heart failure for 1950-69 with the next three decades. A total of 1,075 developed heart failure and they were followed for 10 years. The researchers calculated that the risk of death fell by about one-third.
In the 1990s, 59 percent of the men had died within five years, a drop from 70 percent in the earlier period. For women, the five-year death rate dropped to 45 percent from 57 percent.
"It's not a huge change. But it's the first time that such a study has showed our treatments are impacting on the survival of patients," said Dr. Margaret M. Redfield of the Mayo Clinic, who was not involved in the study.
The researchers suspect the number of new cases for men remained unchanged because of gender differences in the causes of heart failure. Treatment has improved vastly for high blood pressure, a prominent cause for women. More people are surviving heart attacks, a main cause for men, and the damage to their heart makes them vulnerable to heart failure, Levy said.
A second study in the journal suggests that a widely used medication for heart failure, digoxin, a type of digitalis, could be dangerous for women.
Researchers at Yale University looked at data from an earlier study to see if digoxin affected men and women differently. That study determined that digoxin, which has been used for centuries and makes the heart contract more forcefully, did not reduce deaths overall but did result in less hospitalization.
Researcher Dr. Harlan Krumholz said they were surprised to find that women in the study who took digoxin died more frequently (33 percent) than women who took a dummy pill (29 percent). They calculated that digoxin increased the risk of death in women by 23 percent. There was no difference in the death rate among men.
Acknowledging their study was not conclusive, Krumholz said: "This analysis raises the possibility that digoxin may, in fact, be harming women."
More than 25 million prescriptions for digoxin are filled in the United States each year, many of them for heart failure, according to researchers.
Dr. Mihai Gheorghiade of Northwestern Memorial Hospital said doctors might want to consider lower doses for women but they shouldn't stop using what he considers a good, inexpensive drug.
Added Dr. Sidney Smith, chief science officer of the American Heart Association: "A study like this raises some questions, but I think we need more information before we would just say out of hand that some women might not benefit," he said.
On the Net:
New England Journal: http://nejm.org
American Heart Association: http://www.americanheart.org