Osteoporosis drug linked to irregular heartbeat

Women who have used alendronate are nearly twice as likely to develop the most common kind of chronically irregular heartbeat — atrial fibrillation — than those who have never used it, according to research from the Group Health Center for Health Studies and the University of Washington.

The findings were published in the April 28 issue of Archives of Internal Medicine.

Merck markets Fosamax (alendronate), the most widely used drug treatment for osteoporosis, explained study leader Susan Heckbert, MD, PhD, MPH, a professor of epidemiology and scientific investigator in the Cardiovascular Health Research Unit at the University of Washington. The FDA approved the first generic versions of the drug in February.

"We studied more than 700 female Group Health patients whose atrial fibrillation was first detected during a 3-year period," Heckbert said in a press release from Group Health. She and her colleagues compared those women to over 900 randomly selected female Group Health members matched on age and high blood pressure to serve as controls.

"Having used alendronate [at any time point] was associated with an 86% higher risk of newly detected atrial fibrillation compared with never having used the drug," said Heckbert, who is also an affiliate investigator at the Group Health Center.

She said physicians need to exercise good judgment "to weigh the risks and benefits of any medication for any individual patient," she said in the press release. "For most women at high risk of fracture, alendronate's benefit of reducing fractures will outweigh the risk of atrial fibrillation."

However, "Women who are at high risk of fractures but who also have risk factors for atrial fibrillation - such as heart failure, diabetes or coronary disease - might want to discuss alternatives to alendronate with their health care providers," Heckbert noted.

Estrogen therapy is one alternative that can lower the risk of fractures, she said. But the national Women's Health Initiative, on which she also serves as an investigator, showed there are other heart risks associated with combining estrogen with progesterone.

About one in 100 people — and nearly nine in 100 people older than 80 years — have atrial fibrillation, Heckbert said.

"This study will help medical teams better inform their patients about the risks associated with Fosamax, helping us make the best treatment decisions for managing osteoporosis," Christine Himes Fordyce, MD, a Group Health family practitioner, said in the press release.

For more information:
Heckbert SR, Li G, Cummings SR, et al. Use of alendronate and risk of incident atrial fibrillation in women. Arch Intern Med. 2008;168(8):826-831.