TUESDAY, March 22 (HealthDay News) -- Use of a class of cholesterol-lowering drugs called fibrates is on the rise in the United States despite research that suggests they may not do much to improve health, researchers say.
Fibrates are often prescribed to people with low levels of HDL ("good") cholesterol and high levels of triglycerides, a harmful form of fat circulating in the blood, experts explained.
The new study isn't questioning the ability of fibrates to lower triglycerides, said lead study author Cynthia A. Jackevicius, an associate professor of pharmacy at Western University of Health Sciences in Pomona, Calif. Fibrates have also been shown to have a "modest" effect on raising HDL cholesterol. (Statins, another hugely popular family of cholesterol drugs that includes brands such as Lipitor and Zocor, are used to lower LDL, or "bad, cholesterol.)
The real question, according to the study authors, is whether any decline in blood fats linked to fibrate use translates to a benefit to users' health.
They point to two recent large trials conducted in people with diabetes that found that taking fenofibrate, one type of fibrate, did not lower the risk of having a heart attack or dying compared to taking statins alone.
Fenofibrate is sold in a generic form and under the brand names Tricor, Antara, Lipofen and Triglide, among others, the researchers said.
"In some recent studies, the fibrates, particularly fenofibrate, was not found to reduce the chances of having a heart attack or of saving lives," Jackevicius said. "Just because the medicine may improve the cholesterol profile doesn't mean it also decreases the chance of a heart attack or death."
The study is published in the March 23/30 issue of the Journal of the American Medical Association.
There is some research on fibrates that has shown a benefit in warding off heart attacks, although not overall mortality, according to the study. But in those studies, patients took another generic fibrate that's been on the market since the 1980s, called gemfibrozil (which raised some safety concerns when combined with certain statins).
But even though most of the positive data on fibrates has come from that older drug, the news research shows the major growth in prescriptions in the United States has come from fenofibrate -- particularly its more expensive brand-name forms, Jackevicius said.
Use of fibrates has increased steadily in the United States, especially for the brand-name fibrate product. Fenofibrates account for more than $1 billion in U.S. sales, according to background information in the study.
In the study, researchers compared U.S. and Canadian prescription data between January 2002 and December 2009.
In the United States, prescriptions for fibrate medication generally more than doubled -- from 336 prescriptions per 100,000 people in 2002 to 730 prescriptions per 100,000 people in December 2009. The increase in Canada wasn't as steep, from 402 to 474 per 100,000 people.
And in the United States, prescriptions specifically for fenofibrate nearly tripled -- from 150 prescriptions for every 100,000 people in 2002 to 440 for every 100,000 people in 2009. In Canada, fenofibrate's use rose much less steeply, from 321 to 429 per 100,000, the study found.
The researchers also found that physicians tended to prescribe the brand-name drug over generic fenofibrate in the United States, but not in Canada, while costs for fibrates for every 100,000 people were nearly three times higher in the United States than in Canada.
A generic form of fenofibrate has been available in Canada much longer than in the United States, Jackevicius noted.
She said the finding raised a key question for Americans consumers: "Why use the brand name drug if you can use in the less expensive generic?"
Despite the lack of benefit shown in the two studies in diabetics, Dr. Jorge Plutzky, an American Heart Association spokesman and director of the Brigham and Women's Hospital vascular disease prevention program, said that fibrates remain an important option for some patients, particularly those who've had a heart attack already and/or have very high triglyceride levels (above 300 milligrams per deciliter of blood) and very low HDL (below 35 mg/dL).
And he believes that, in a deeper look at the data in the studies of diabetics in the subgroup of people with very high triglycerides and very low HDL, fibrates may be beneficial. In addition, some patients in those studies were also taking statins, which may have obscured the benefits they might have derived from fibrates, Plutzky said.
"When physicians see patients whose LDLs [cholesterol] are well-controlled, but who still have residual risk with elevated trigylcerides and low HDL, fibrates are a potential target for that," Plutzsky said. "The evidence has not been a strong as we would have liked, but there is also evidence I would not be willing to ignore."
Doctors typically choose fenofibrate over older, generic gemfibozil because the former is a once-a-day dose, while the latter has to be taken twice a day, he said, and people are more likely to take a once-a-day medication. Whether people take the generic or the brand name is usually determined by the insurance plan, he added.
Researchers stressed that this research is not about statins, which have been shown in numerous studies to reduce the chances of a heart attack by lowering LDL cholesterol.
They also emphasized that patients should continue taking their fibrates as prescribed and talk to their doctor if they have any questions, Jackevicius said.
Eating a healthy diet, exercising, losing weight and improving diabetes control can help also improve the cholesterol profile, the researchers said.
The American Heart Association has more on cholesterol.
SOURCES: Cynthia A. Jackevicius, Pharm.D., M.Sc., associate professor, pharmacy, Western University of Health Sciences, Pomona, Calif.; Jorge Plutzky, M.D., American Heart Association spokesman, and director, Brigham and Women's Hospital, vascular disease prevention program; JAMA, March 23/30, 2011.
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