New Bisphosphonate Study Again Links Drug to Atrial Fibrillation

A newly published study on the link between osteoporosis drugs and atrial fibrillation (AF) hoped to clear up some of the conflicting results from previous studies.

Atrial fibrillation is a common heart irregularity that means the upper chamber of the heart beats chaotically which can mean a lessening in the efficient movement of blood to the lungs and around the body. AF can result in dizziness, fainting and fatigue – and in rare cases, a blood clot, stroke or heart attack that can be fatal. Researchers from Maimonides Medical Center in Brooklyn wanted to evaluate the risk of serious atrial fibrillation that involved hospitalization, heart attack and stroke with the use of bisphosphonates.

Published in the October issue of the journal Chest, the official publication of the American College of Chest Physicians, researchers revisited the literature including six observational studies and randomized controlled trials conducted from 1966 to 2012.

There were 757 cases of AF among those taking bisphosphonates including 480 hospitalizations and 87 patient deaths. Among cases of cardiac arrhythmias there were 2,344 which were linked to bisphosphonate use. Among those were 1,432 hospitalizations and 437 patient deaths.

Researchers concluded that bisphosphonates had a statistically significant risk to AF requiring hospitalization while they did not result in a heightened risk of stroke or death from a heart attack.

Questions about this class of drugs are not new. As far back as 2007, the FDA Food and Drug Administration (FDA) announced it was reviewing bisphosphonates after a published article in The New England Journal of Medicine reported similar increased rates of risk.

Specifically named were Reclast and Fosamax, however in a follow-up, the FDA seemed to retreat and said “no clear association between overall bisphosphonate exposure and the rate of serious or non-serious atrial fibrillation was observed.”

Besides Reclast and Fosamax, examples of bisphosphonates also include Boniva, Actonel and Atelvia. They are controversial because they interfere with the natural process of bone loss and rebuilding. As a result, bisphosphonates have been linked to necrosis of the jaw (ONJ), which is also known a jawbone death and atypical fractures of the femur.

The FDA approved Fosamax in 1995 to treat osteoporosis associated with menopause. Two years later it was approved to prevent osteoporosis. Fosamax is the only osteoporosis drug that promises to build bone in postmenopausal woman. It works by slowing bone loss, again part of that natural cycle, but after about three years, the suppression of bone loss also affects the formation of new bone and bone created tends to be brittle and less dense, according to urogynecologist, Dr. William Banks Hinshaw, who studies bone health. He believes bisphosphonates never completely leave the body.