Much media attention has been paid to the new guidelines from American College of Cardiology/American Heart Association (ACC/AHA) on the primary prevention of cardiovascular disease. Based on new clinical trial data, ACC/AHA no longer recommends that healthy adults without cardiovascular disease — emphasis on without cardiovascular disease — take daily aspirin for the primary prevention of cardiovascular disease.

This change, while significant, is highly nuanced and dependent on a clear understanding of the difference between primary prevention and secondary prevention. Primary prevention is the sum of efforts to prevent an event that an individual has never had in the past. An example of primary prevention is administration of vaccines, which help protect against contracting a disease in the first place. Secondary prevention involves reducing the impact of current diseases and seeking to prevent future recurrences of events that have already occurred. Quitting smoking after being diagnosed with chronic obstructive pulmonary disease (COPD) and completing cardiac rehabilitation after having a heart attack represent common examples of secondary prevention.

The new ACC/AHA guidelines address the primary prevention of cardiovascular disease in individuals currently without cardiovascular disease. For decades, the prevailing notion was that a low-dose aspirin may prevent cardiovascular disease before it begins. However, recent large randomized trials have shown this perceived benefit to be negligible while increasing the risk of a serious bleeding event. This was true even in individuals with diabetes who have an inherently higher risk for cardiovascular disease. Based on this new evidence, low-dose aspirin is no longer recommended for primary prevention in individuals at low risk for cardiovascular disease, adults older than age 70, or individuals at increased risk of bleeding.

Let’s take an 80-year old woman who lives independently and has no health problems aside from osteoarthritis. She does not have cardiovascular disease.  Should she be using aspirin? This is the primary population affected by the new guidelines. Given the results of both trials, aspirin is unlikely to prevent her from having a future heart attack or stroke. In fact, aspirin may increase her risk of future bleeding.

For individuals between ages 40 and 70 with a higher cardiovascular risk profile (family history of premature myocardial infarction, inability to achieve lipid/blood pressure/glucose targets, or elevated coronary artery calcium score), patients and their providers should have an informed discussion about the risks and benefits prior to making a shared decision about whether to initiate low-dose aspirin for primary prevention. Fortunately, health care providers have additional objective data to help guide their decision-making process, such as the Atherosclerotic Cardiovascular Disease (ASCVD) risk score, with scores greater than 10% suggesting the benefits of aspirin for primary prevention begin to outweigh the risks.

In short, the new guidelines mean that aspirin is no longer recommended for those without cardiovascular disease. This change affects millions of people. However, these recommendations do not apply to an estimated 121 million individuals — nearly 48 percent of the population — that already have cardiovascular disease (including stroke), where the benefits of aspirin are well-established.

The media effect. You would not know this from reading the headlines, many of which are misleading for patients. Headlines such as “Daily aspirin to prevent heart attacks no longer recommended for older adults” and “Don’t take an aspirin a day to prevent heart attacks and strokes” suggest that patients should stop taking aspirin. These types of headlines are misleading, if not downright false, for millions of people who should continue to take aspirin as directed. Some outlets did better than others — with headlines such as “Daily low-dose aspirin no longer recommended by doctors, if you’re healthy,” — by at least suggesting the recommendations only applied to some people.

Why should these headlines give us pause? Because context and responsible messaging matters. Research from the fields of neuroscience and cognitive psychology is instructive. Predictive coding, for instance, suggests that the brain actively predicts what input it will receive, rather than just passively processing information as it arrives. In other words, the first few words of a sentence can bias a person’s view of what comes next. Similar studies have shown that the brain fills in the blanks, creating illusions based on context and previous memories to create a picture with incomplete or partial information, based on our prior experiences, memories, and knowledge base. One fascinating example of this is “typoglycemia,” a phenomenon that eilaxpns why our bainrs are albe to raed and cnrehmpeod seteenncs flul of tirpchyaapgol eorrrs.

Because the brain tends to “fill in gaps,” omitting key information from a headline or placing the most important information at the end of a headline makes it vulnerable to being hijacked by a reader’s brain. This is exacerbated by the fact that many readers do not read beyond the title of an article, with most scrolling through only about half of an article.

The impact. These headlines are already having an effect. Dr. Siddharth Sehgal, a vascular neurologist at Lahey Hospital and Medical Center, recently counseled a patient about treatment for her ischemic stroke, including the need to take aspirin on a daily basis. Her response? “But doc! I just read on the news that aspirin is no longer recommended to prevent heart attack and stroke.” Dr. Sehgal then spent time addressing her confusion and clarifying that there is strong evidence for the use of aspirin for secondary stroke prophylaxis. The patient understood and confirmed that she would take the aspirin as recommended.

Dr. Sehgal and his patient had a happy outcome. But the media does a disservice to patients by overly reducing nuanced, complex studies and guidelines to too-easily digested soundbites. At the same time, physicians must step up to demystify changes and ensure that patients and their families truly understand the best-known evidence. Working together, researchers, physicians, and (social and traditional) media outlets can each do our part to advance patient understanding and improve health outcomes.

Olubadewa A. Fatunde is an internal medicine resident.

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