Use of fibrates in the U.S. more than doubled between January 2002 and December 2009 despite evidence showing mixed results in its clinical effectiveness, according to a recently published study.

College of Pharmacy Associate Professor of Pharmacy Practice and Administration Cynthia Jackevicius, PharmD, is the lead author of the study, “Use of Fibrates in the United States and Canada,” published in the Journal of the American Medical Association. One of the co-authors is 2010 College of Pharmacy alumnus Daniel Carreon, PharmD.

The authors found that, despite the absence of supporting evidence, use of fibrates in the United States more than doubled between January 2002 and December 2009. By contrast, fibrate usage remained relatively stable in Canada during the same period. Most of the change in the U.S. was attributed to an increase in branded fenofibrate usage; in Canada the opposite pattern emerged, as generic fibrate usage increased. Patent protection actions have kept generic fenofibrate out of the U.S. market until recently, while it has been available in Canada for more than a decade.

“There is a strong belief that lower triglycerides with these drugs will lower risk of heart attacks and dying – it makes sense, but unfortunately has not been demonstrated that these medications, especially fenofibrate, can reduce these risks,” Jackevicius said.

Costs per capita related to fibrates were three times higher in the U.S. than in Canada. If fenofibrate had been used in a pattern that was similar to that in Canada (similar rates and access to generic products), the U.S. would have saved $364 million per year based on 2008 numbers.

Evidence that fibrates have clinical benefit is mixed, with most studies focusing on lipid effects, according to the study.

Fibrates mainly lower the level of one type of cholesterol, called triglycerides, which measures the amount of fat circulating around in the blood, Jackevicius said.

“However, in the most recent clinical studies, which were conducted in patients with diabetes, fenofibrate was not found to reduce the chance of having a heart attack or saving lives,” she said. “So just because the medication affects the level of triglycerides doesn’t mean that it reduces heart disease events or death, until it is proven in studies.”

Current U.S. guidelines recommend that fibrates without regard to type should only be considered for reducing very high levels of triglycerides to prevent pancreatitis, for treatment of dysbetalipoproteinemia, and as supplemental therapy to statins in patients with diabetes and

high non-high-density lipoprotein cholesterol, according to the study.

The 2006 revision of the Canadian guidelines now more cautiously reserves treatment with fibrates for severe hypertriglyceridemia. Continued caution is warranted in guideline recommendations for fibrates as we await evidence of clinical benefits.

The complete citation is: Cynthia A. Jackevicius, PharmD, MSc, Jack V. Tu, MD, PhD, Joseph S. Ross, MD, MHS, Dennis T. Ko, MD, MSc, Daniel Carreon, PharmD, Harlan M. Krumholz, MD, SM. Use of Fibrates in the United States and Canada. JAMA. 2011;305(12):1217-1224.

Click here to view the study.