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NEW YORK (Reuters Health) - Women who have ever used alendronate, also known by the trade name Fosamax, may have an increased risk of atrial fibrillation, according to findings from a new study. However, the overall risk is low and is likely outweighed by the benefits of fracture prevention in patients with osteoporosis if they have no other risk factors for atrial fibrillation, the investigators conclude.
The unexpected finding of an increased risk of serious atrial fibrillation associated with the use of this class of drugs, called bisphosphonates, was found in two clinical trials, Dr. Susan R. Heckbert and associates note. To see if alendronate increases the risk of atrial fibrillation in a clinical practice setting, as opposed to a trial, the researchers analyzed data from patients in the Atrial Fibrillation Study being conducted at Group Health, an integrated health care delivery system in Washington State.
Alendronate is used to treat or prevent osteoporosis, a disease that causes the bones to become porous and to break easily, in women who have undergone menopause or individuals who are at risk for osteoporosis for other reasons, such as those who take steroids regularly.
Heckbert, at the University of Washington in Seattle, and her team identified 719 women with atrial fibrillation diagnosed between 2001 and 2004, and randomly selected 966 matched "control" subjects without atrial fibrillation also enrolled in Group Health. Most subjects were in their 70s.
Atrial fibrillation occurs when the electrical signal to the heart becomes disordered and the two upper chambers, the "atria," to contract rapidly and irregularly. This keeps the heart from efficiently pumping blood and may cause chest pain, stroke, heart attack or heart failure. The condition can occur rarely, frequently or persistently, and can last for years.
The researchers found that more atrial fibrillation patients than controls had ever used alendronate -- 6.5 percent vs 4.1 percent. The subjects who had ever taken alendronate had an 86 percent increased risk of developing atrial fibrillation compared with those who never used a bisphosphonate.
