Many people living with the heart rhythm disorder known as atrial fibrillation may be taking unneeded blood thinners, a new study suggests.
These blood thinners, which include aspirin, Plavix and warfarin, are believed to reduce the risk of stroke that can come with atrial fibrillation. But for many atrial fibrillation patients with a low stroke risk, the medications might actually increase both bleeding and stroke risk, researchers reported.
The way most doctors decide whether a patient needs a blood thinner is by using a simple score called CHADS2, which assigns points to patients based on age and other medical risks. A score of 2 is usually needed to recommend a blood thinner, the researchers explained.
But, “people are realizing that the CHADS2 scores are putting too many people above the threshold – it’s pretty easy to get a 2,” explained study author Benjamin Horne, an adjunct assistant professor of biomedical informatics at Intermountain Medical Center Heart Institute in Utah. “It’s better than flipping a coin, but there are many other scores out there that are more predictive,” Horne said. “The problem with those scores is that it is difficult and time-consuming to use.”
For the study, Horne and his colleagues collected data on nearly 57,000 patients with atrial fibrillation and a CHADS2 score of 0-2. Patients were divided into groups receiving aspirin, Plavix or warfarin or no blood thinner.
At three and five years, the rates of stroke, mini-stroke and major bleeding were higher with any blood thinner, compared with no treatment, the researchers found. The rates of these outcomes were lower among patients taking warfarin than among those taking aspirin or Plavix, the study authors added.
I have long believed that low stroke risk Afib patients should avoid blood thinners. But I was very surprised when patients on warfarin fared better than those on aspirin. Warfarin or Coumadin is just rat poison and the therapeutic levels are very close to the toxic levels. It may be that regular blood tests required for patients on warfarin increases the safety.
On the flip side, this study further illustrates the dangers of taking even a low-dose (baby) aspirin daily. Too often people think that aspirin is harmless. In reality, it could never meet FDA standards for safety but was a standard of practice long before the FDA was formed.
The Bottom Line:
If you are on any blood thinner please review this study with your PCP. Inquire about your CHADS2 score. Aspirin has proven benefits for patients that have already suffered a heart attack. However, numerous studies indicate that the risk of major bleeding, stroke or mini-stroke outweigh the potential benefits for most of us.
Source: March 17, 2017 National Institutes of Health