Osteoporosis Drugs: Risk to the Heart?
Fosamax, Other Bisphosphonate Drugs Studied; No Reason to Stop Use, Experts Say
Atrial Fibrillation Study continued...
The study doesn't prove that Fosamax caused atrial fibrillation. The study was observational, meaning that patients weren't randomly assigned to take Fosamax.
The results held when the researchers weighed other heart rhythm risk factors. "It was a robust finding," says Heckbert, cautioning that observational studies can't address every possible influence on the data.
Heckbert and colleagues did the study after other researchers last year reported an increased rate of atrial fibrillation associated with the osteoporosis drug Reclast, which, like Fosamax, is a bisphosphonate.
But in another recent study, Danish researchers found no evidence of increased risk of atrial fibrillation in women taking bisphosphonates.
"Medicine is like that," Heckbert says. "We don't always find the same things."
Real Risk or Fluke?
WebMD asked two independent experts to review Heckbert's study.
"The evidence here is interesting, but I'm not going to put this at a high level of confidence at this point," Edward Puzas, MD, tells WebMD. Puzas is a professor of orthopaedics, director of the Osteoporosis Center, and director of orthopaedic research at the University of Rochester School of Medicine in Rochester, N.Y.
"I think you're going to see articles coming out on both sides of this right now, and my prediction is that in the end, it's going to sort itself out that there's little if any risk associated with cardiovascular issues and these bisphosphonates," Puzas says.
"I'm not ready to believe that the bisphosphonates, certainly as a class, have got any real potential serious adverse event with regard to atrial fibrillation," Puzas says. "Sometimes, where there's smoke there's fire, but many times, when you retrospectively ... look at these articles, they really do amount to statistical fluke or a statistical fluctuation, and it's not until other people demonstrate them in other trials in a more prospective, rigorous fashion that you can actually believe the evidence.
"If I were treating a new patient and about to put them on a bisphosphonate, I would evaluate their cardiac status with an extra eye toward looking at atrial fibrillation," says Puzas, adding that he wouldn't rule out bisphosphonates based only on cardiovascular risk factors.