Although some patients developed liver problems that forced them to stop taking the medication, researchers believe the benefits of this approach outweigh its risks. Still, specialists said more study is needed to establish its safety before it can be recommended.
"This was a very gutsy study," said Dr. John LaRosa of State University of New York in Brooklyn, who led the large international study. "This is new territory."
Statin drugs such as Lipitor, Zocor and Mevacor have shown an impressive ability to lower LDL or "bad" cholesterol and reduce the risk of heart trouble. Recently, some doctors have advocated a much more aggressive strategy of driving cholesterol levels down even farther for certain people.
A study of this approach was funded by and involved many doctors with ties to Pfizer Inc., which makes Lipitor. It is one of six statins on the market. Guidelines advise people at high risk of a heart attack to get LDL to 70 and those at moderate risk to aim for 100.
A previous study found that giving high-dose statins to lower cholesterol below 100 helped people who recently suffered a heart attack. This study, in contrast, involved people who had clogged heart arteries that occasionally cause chest pain but were in no immediate danger of a heart attack. Up to 13 million Americans are in that category.
About 10,000 people in 14 countries took either 10 milligrams or 80 milligrams of Lipitor and brought their LDL levels to 101 and 77, respectively.
After nearly five years, 10.9 percent of those on the low dose had died or suffered a stroke, heart attack or other big problem, compared with 8.7 percent on the high dose. That means that patients on high doses had a 22 percent lower risk.
That is better than doctors had expected, LaRosa said.
"Most of us thought that when you got to 100, going lower would be marginal at best," he said.
However, about 1.2 percent developed signs of liver inflammation on the high dose versus 0.2 percent of the others, which is in line with other studies that tested high doses of statins.
Usually the inflammation clears up when people are taken off the drug, but patients would need to be aggressively tested and monitored for this condition, said Dr. Sidney C. Smith, an American Heart Association spokesman and cardiologist at the University of North Carolina.
Results also might vary with a different statin, he said. Other brands are Bristol-Myers Squibb's Pravachol, Novartis Pharmaceuticals' Lescol, AstraZeneca's Crestor, and Zocor and Mevacor, sold by Merck & Co.
In an editorial in the medical journal, Dr. Bertram Pitt of the University of Michigan School of Medicine said it is not known if aggressively lowering LDL is the best strategy for cutting heart attack risk or whether high-dose statins are the best ways to do that. Other approaches, such as raising "good" cholesterol or adding other drugs to conventional doses of statins, need to be compared, he said.
Two studies under way should provide more information within a year, Smith said.
"We need further reassurance as to the safety of this approach before we can advocate a major shift" in cholesterol goals, Pitt wrote.
In other news at the conference, another large international study funded by Pfizer found a newer combination of high blood pressure drugs to be safer and more effective than a different combo that was recently linked to a higher risk of developing diabetes.
Doctors from Imperial College in London tested diuretics, or water pills, plus the beta blocker atenolol, against the calcium channel blocker amlodipine, sold as Nordasc by Pfizer, and the ACE inhibitor perindopril, sold as Aceon by CV Therapeutics and Solvay Pharmaceuticals in the United States and as Coversyl in Europe.
The study of nearly 20,000 people was stopped early, in December, because deaths were about 15 percent higher in the group on the older beta blocker combo. Preliminary results suggest that people on the newer treatment had lower risks of strokes and heart problems.
Researchers say more study is needed to determine whether the results are due to the specific drugs or the combination of them.
By Marilynn Marchione