Studies Identify Possible New Uses for Statins.
Other papers published in the past few years have shown evidence that the statins, which were developed and are approved for lowering serum levels of low-density lipoprotein cholesterol, may also reduce inflammatory and thrombotic activity within blood vessels.
Neither of these actions nor the impact of the statins on bone density has been definitively proved, yet the suggestive findings have prompted some experts to envision striking new uses for the statins.
"It's almost amazing. Statins lower the risk of coronary disease, they lower the risk of stroke, perhaps they increase bone density, and they're being looked at for preventing dementia and breast cancer. If you had a moderately lower price for statins, and if their good safety profile continues, you can start to ask whether they should be used by everyone who is older than 65," said Dr. Lewis K. Kuller, chairman of the department of epidemiology at the University of Pittsburgh.
And price may soon become less of a barrier as the statins will shortly begin to move off patent and come to market as generic formulations.
The four reports that linked statins to a reduced risk of bone fracture were all retrospective, case-control studies.
A collaboration between researchers in Switzerland and Boston University reviewed more than 28,000 people who had used lipid-lowering drugs and more than 63,000 controls in the United Kingdom. During about 10 years of tracking, more than 3,900 of these people had a bone fracture.
The analysis showed that those who had used a statin were 40%-50% less likely to have had a bone fracture than those who did not; fibrates and other lipid-lowering drugs did not have this effect (JAMA 283:3205-tO, 2000).
Researchers at Brigham and Women's Hospital in Boston followed more than 6,000 New Jersey residents, aged 65 or older. Statin use was linked with a 40%-50% drop in the risk of hip fracture. (JAMA 283:3211-16, 2000).
A study led by investigators from Harvard University in Boston collected data from six health maintenance organizations in the United States. The analysis focused on more than 3,600 women aged 60 or older.
Women who had received a statin for 13 or more months during the prior 2 years had an adjusted risk reduction of about 50%, compared with women who had not used a statin. This effect was not seen in women who had used other types of lipid-lowering drugs (Lancet 355:2185-88, 2000).
Researchers in London reviewed bone mineral density measurements done annually since 1989 for 1,003 women. Among 41 women who were taking a statin at the time of their scan, bone density readings were about 10% higher when compared with a control group of 100 women (Lancet 355:2218-19, 2000).
This surprising link, which was first suggested last year in a report from animal studies, left experts scrambling to come up with a plausible mechanism to explain the effect.
One possible hint is that the statins block an early step in the enzymatic pathway that eventually turns acetyl CoA into cholesterol, while the nitrogen-containing bisphosphonates--alendronate and risedronate--block a step that occurs later in this pathway.
The authors of all four reports and an editorial that appeared with the two JAMA papers stressed that the association between statin use and increased bone density had to be confirmed by controlled, randomized studies. Even though statins are safe and are on the U.S. market, they should not now be prescribed to prevent or treat osteoporosis, they concluded. Some companies that make statins are considering sponsoring such trials, said Dr. Stephen R. Cummings, a professor of medicine and epidemiology at the University of California, San Francisco.
The concept of using statins is exciting, he commented, because "statins were associated with an increase in bone mass rather than simply prevention of further bone loss. There are few drugs that increase bone mass and are good to use clinically so this would be an extraordinary effect."
"Drugs that truly stimulate new bone formation could, at least in theory, actually cure osteoporosis," said Dr. Michael McClung, director of the Oregon Osteoporosis Center in Portland. "Even if statins were of equal efficacy with current [osteoporosis] drugs, they would be an attractive addition because one drug could accomplish two therapeutic objectives."
This last possibility, that statins might be a two-for-one drug, has probably aroused the most interest.
"If one drug class could prevent or treat osteoporosis and coronary disease simultaneously, it would be a terrific boon," commented Dr. David J. Maron, director of preventive cardiology at Vanderbilt University Heart Institute in Nashville, Tenn.
"Patients and physicians would be more willing to treat hypercholesterolemia in women with a high risk for osteoporosis, and they would be more willing to prevent or treat osteoporosis with statins because there would be another benefit from drugs that have a great safety profile. I think that women would be less ambivalent about statin therapy than they are about estrogen replacement for preventing osteoporosis," he said.