LOS ANGELES — A heart disease treatment that many doctors consider to be fringe medicine unexpectedly showed some promise in a federal study clouded by ethical and scientific controversy, causing debate about the results.
The study took 10 years, cost taxpayers $30 million, involved several doctors convicted of felonies and spurred a federal inquiry into patient safety. Even the lead researchers say the treatment cannot be recommended without further research.
The study tested chelation (pronounced "kee-LAY'shun") — periodic intravenous infusions that proponents say may help remove calcium from hardened arteries around the heart. Chelation has long been used to treat lead poisoning but its safety and value for heart disease are unproved.
The heart disease version involves a different drug that does not have government approval for any use in the United States. However, alternative medicine practitioners have been ordering it custom-mixed from compounding pharmacies.
More than 100,000 Americans use chelation. Treatments cost $90 to $150 apiece, usually are done weekly for 30 weeks and then less often, and are not covered by insurance.
On Sunday at an American Heart Association conference in Los Angeles, researchers said that a chelation mixture they tested in a study of 1,708 heart attack survivors led to fewer complications — repeat heart attacks, strokes, deaths, hospitalization for chest pain or need for an artery-opening procedure.
Four years after treatment, 26.5 percent of the chelation group had one of these problems versus 30 percent of those given dummy infusions.
However, 17 percent of participants dropped out before the study ended, and only 65 percent had all 40 infusions they were supposed to get. The missing and incomplete results make it unclear whether the benefit credited to chelation could have occurred by chance alone. The results have not been published in a medical journal or vetted by independent scientists, another reason doctors are leery.
"The study in my view is inconclusive," said Dr. Steven Nissen, the Cleveland Clinic's cardiovascular chief who had no role in the research. "Chelation has been practiced by physicians on the extreme fringes of medicine" and many involved in this study offer "a variety of other quack therapies," Nissen said.
Others including the Heart Association praised the government for doing the study.
"Patients are doing this with or without our permission" so it's important to test, said Dr. John Harold, president-elect of the American College of Cardiology and a doctor at Cedars-Sinai Heart Institute in Los Angeles.
Dr. Gary Gibbons, director of the National Heart, Lung and Blood Institute, which funded the study with the National Center for Complementary and Alternative Medicine, called it "a first step" and urged caution about results that suggest "a marginal benefit."