He also said that the primary end point was a composite of many different cardiovascular events, and data for individual events were not available. In addition, there remained an absence of clear biological rationale.
Interest in chelation therapy has been increasing, at least until recently, according to national data. In 2007, nearly 111,000 people received chelation, an almost 68% increase from 2002.
But the procedure can be harmful, especially if infusions occur quickly, causing hypocalcemia. Three of those cases that led to patient death were recorded in a 2006 Centers for Disease Control and Prevention report.
"To suggest that [chelation therapy] is steeped in controversy is an understatement," said Dr. Paul W. Armstrong, professor of medicine at the University of Alberta in Edmonton, who commented on the trial at a press briefing. "We owe the investigators a debt of gratitude for undertaking this subject," he said. But, "the results are hypothesis generating and not practice changing."
The National Center for Complementary and Alternative Medicine and the National Heart, Lung, and Blood Institute funded the study. Dr. Armstrong received research grants from several companies including Boehringer Ingelheim and AstraZeneca. Dr. Antman and Dr. Williams had no relevant disclosures. Dr. Goldstein is the medical editor of Cardiology News.