Beta Blocker Doesn't Help Children With Heart Failure
TUESDAY Sept. 11, 2007 -- Carvedilol, a newer member of the beta blocker drug family that has been effective for adults with heart failure, did not help children with the condition, a new study found.
The rate of improvement -- and the lack of it -- was almost exactly the same for 103 young heart-failure patients given the drug as it was for 54 youngsters who got a placebo.
"Heart failure in children is both not common and a different kind of disease" than in adults, said Dr. Robert E. Shaddy, division chief of cardiology at Children's Hospital of Philadelphia, and lead author of the report.
Adults suffer heart failure, a progressive loss of the heart's ability to pump blood, because of coronary artery disease, Shaddy said. "Children rarely get it," he said. "In them, it is caused either by heart muscle problems or problems related to congenital malformations."
Among the 103 young people assigned to carvedilol, 56 percent improved, 19 percent were unchanged, and 24 percent worsened. Among the 54 who got conventional treatment and a placebo, 56 percent improved, 30 percent worsened, and 15 percent were unchanged.
The study findings are published in the Sept. 12 issue of the Journal of the American Medical Association.
It's still possible that the drug, which is marketed as Coreg, might help some children with heart failure, Shaddy said. An analysis of subgroups of patients in the study did show some improvement for children whose problem rested in the left ventricle, he said. "What I recommend to families based on this study is that there might possibly be a differential effect, which depends on the type of heart problem. But we were unable to prove it," he added.
Much larger studies would be needed to prove such a benefit in pediatric heart failure, and such studies would be hard to do, because the condition is rare, Shaddy said.
Dr. Samuel S. Gidding, an attending cardiologist at the Nemours Cardiac Center in Wilmington, Del., who wrote an accompanying editorial in the journal, said, "This study was underpowered [small in numbers] to show a benefit. The causes of heart failure in children are very different from the causes of heart failure in adults. Also, the drug is metabolized more quickly in children, so some patients are under-dosed, and there is a different response to drugs based on the disease class."
The study shows the hazards of extrapolating treatment results in adults to children, Gidding said. "We would need to be a lot more aggressive in trials in children to show what works and what doesn't work," he said. "We need much bigger clinical trials in kids rather than imposing conclusions from adult trials."
If further studies are to be done, Shaddy said, "we would recommend that they be done with a more homogeneous group, children with one type of heart disease."
"Children are not little adults," Gidding added. "In adulthood, there is a lot more wear and tear on the body."
You can learn more about beta-blocker drugs from the Texas Heart Institute.
Posted: September 2007