We are generally pretty enthusiastic about aspirin. Unlike other pain relievers, aspirin has cardiovascular benefits, particularly for those who already have heart disease. In addition, regular aspirin use has been associated with a lower risk of a wide range of cancers. (You can read more about that here and here.)
Risks as Well as Benefits:
Aspirin is not innocuous, however. It has well-known gastrointestinal side effects and has been associated with bleeding ulcers. That is a very serious outcome.
We are also concerned about another risk. Epidemiologists have found links between aspirin use and the debilitating eye disease, age-related macular degeneration. This connection surfaced about three years ago. Here is what we wrote at that time:
Aspirin Is Associated with Macular Degeneration:
In case you missed it, an article was published in the journal JAMA Internal Medicine (formerly the Archives of Internal Medicine) on January 21, 2013, titled “The Association of Aspirin Use with Age-Related Macular Degeneration [AMD].” We felt it was newsworthy and so you will find an overview of the study in our Health News this week.
The editors of JAMA Internal Medicine were very cautious about this research. First, it was an “observational” study. That means it is not the kind of gold-standard research we need to draw definitive conclusions. The best studies are randomized, placebo-controlled trials. Second, an “eloquent Invited Commentary” by Kaul and Diamond about the research concludes that “The association between regular aspirin exposure and the risk of AMD is modest…”
Finally, and most important, the editors explain their concerns about publishing this research:
“The eloquent Invited Commentary by Kaul and Diamond illustrates the great care that must be taken before concluding that an association described in an observational study truly represents a cause-effect relationship. In our discussion of the article by Liew and colleagues, the editors believed that it provided useful incremental data about an important condition. However, as with many good studies, the data are not definitive enough to suggest changes in clinical practice. Rather, we hope the study galvanizes more research on the relationship between aspirin and macular degeneration.
“After the editors decided to accept this article, we discussed the risk that press reports would fall into the trap of reporting this study as definitive. This study provides an opportunity to educate the public about the subtleties and incremental nature of medical research.”
Media Coverage Lacked Nuance:
The editors had reason to be concerned. Much of the subtlety of this study was lost in the following headlines:
“Study links aspirin to blindness”
“Long-term aspirin use linked with increased risk of blindness”
“Aspirin users could double risk of blindness in old age”
“Study: Aspirin use increases blindness risk among elderly”
“Aspirin use may cause age-related blindness”
The headlines are likely to scare the dickens out of most readers. Few will forget the words “aspirin and blindness.” Even if an article points out that association is not causation, that subtlety is likely to be forgotten. Also ignored may be the fact that age-related macular degeneration is relatively uncommon (prevalence of about 1.5% in the American population). Even a doubling of risk still means that there is a relatively small absolute risk of developing this problem with regular aspirin use.
The authors of this research point out that their study confirms findings from another observational study which also found a two-fold increased risk of AMD among regular aspirin users. But what was pretty much ignored in the news reports was their acknowledgement that two large, gold-standard randomized clinical trials (The Physicians’ Health Study and the Women’s Health Study) reported “no increased AMD risk during 7 to 10 years among aspirin users.”
So, What’s the Bottom Line on Aspirin and AMD?
Age-related macular degeneration is certainly worrisome. Even though it is relatively rare it does lead to blindness in as many as 500,000 Americans. That is why it is essential to get regular eye exams to detect any signs of this disease at the earliest stages. This condition can often be treated with some new medications such as Lucentis (ranibizumab), Avastin (bevacizumab), Eylea (aflibercept), Macugen (pegaptanib) or Visudyne (verteporfin). There is also laser photocoagulation therapy.
- The story on aspirin and AMD is confusing. The data are clearly not definitive. If the risk exists, it takes 10 to 15 years to show up. We will need long-term randomized, double-blind studies to establish a cause and effect relationship.
- What should we all do in the meantime? The authors of this research conclude that there is “insufficient evidence to recommend changing clinical practice” regarding aspirin use. In other words, if your doctor believes that aspirin is important for reducing the risk of cardiovascular disease (heart attacks or strokes) or cancer, it is best to follow that advice and not discontinue aspirin suddenly because of scary headlines.
- If an eye exam reveals the early stages of age-related macular degeneration, it is essential to discuss the dangers of continued aspirin use.
More Recent Research:
A meta-analysis evaluated ten studies of this association and found that aspirin use slightly increased the risk of age-related macular degeneration (Journal of Clinical Pharmacy and Therapeutics, Apr., 2015). It had differential effects on the types of AMD, however, increasing the risk of “wet” macular degeneration (neovascularization) and decreasing the risk of “dry” AMD (geographic atrophy). This confirmation that aspirin has a “weak but statistically significant association” with AMD suggests that people who already have this condition and those who may be at higher risk for AMD should definitely follow the advice above and discuss any aspirin use with their doctors.
A different analysis of aspirin studies looked specifically at randomized controlled trials of aspirin for preventing heart disease and considered the side effects found in those studies (US Preventive Services Task Force Syntheses, Sep., 2015). These scientists could detect no difference in the risk of AMD between those taking aspirin and those on placebo.
What Do You Think?
What is your experience with AMD? Have you received treatment? Has it worked? Were you satisfied? Have you experienced AMD after long-term regular aspirin use? We would love to hear your story below.
Should you wish to listen to a radio interview about the pros and cons of aspirin we offer “Aspirin Secrets Revealed,” Show # 842). It tells about the latest research involving aspirin against cancer.
We also have a FREE Guide to Key Aspirin Information.
We try to bring you the stories behind the health headlines and explain the subtleties that are often left out of the popular press. Please let us know how we did with this complex aspirin story.