A new study published on June 20 in the Annals of Internal Medicine has found that people who take a daily low-dose aspirin may be at a higher risk of developing anemia. Researchers discovered that prolonged daily aspirin use increased anemia risk by 20 percent in individuals who were mostly aged 70 and above.
Notably, co-author of the study and professor of medicine at the Duke University School of Medicine in Durham, North Carolina, Harvey Cohen, MD, said that these findings were seen in those who didn’t have any evidence of bleeding in their gastrointestinal (GI) tract.
Dr. Cohen says, “It’s still likely that the anemia was caused by bleeding, it’s just subclinical, or not severe enough to be readily observable. That suggests that people who are receiving low-dose aspirin should be monitored for the potential of iron deficiency, even when they don’t have obvious bleeding.”
Study Finds ‘Hidden’ Blood Loss from Daily Aspirin Use
The study is groundbreaking in its scope, representing the first large-scale investigation into the long-term adverse effects of aspirin, explains a family medicine physician at the Ohio State University Wexner Medical Center in Columbus, Rachael McGuirk, MD, who was not involved in the study.
She shares, “While we already know that aspirin can cause serious bleeding problems requiring hospitalization in some people, this study shows that there can be ‘hidden’ blood loss in those who take daily aspirin, too. Over the years, people who take aspirin can lose small amounts of blood in their stool from stomach irritation.”
Anemia and Bleeding Events Increase with 100 Milligrams of Aspirin
The study analyzed data from approximately 18,000 initially healthy older adults in Australia and the United States. This data constituted a sub-analysis of the ASPREE (Aspirin in Reducing Events in the Elderly) trial, which notably marked the first trial to demonstrate that aspirin did not extend the healthy lifespan of initially healthy older individuals, primarily those aged 70 and older.
Over a median observation period of 4.7 years, the incidence of anemia was found to be 51.2 events per 1,000 person-years in the group that consumed 100 milligrams (mg) of aspirin daily. In contrast, the placebo group, who took a sham pill instead of aspirin, exhibited an incidence rate of 42.9 events per 1,000 person-years. Furthermore, the estimated likelihood of developing anemia within five years was 23.5 percent for the aspirin-taking group, compared to 20.3 percent in the placebo group.
The study also revealed an increased likelihood of clinically significant bleeding events among those taking aspirin, with 3 percent of the aspirin group experiencing at least one event, compared to 2.1 percent in the placebo group.
Anemia Linked to Cognitive Problems and Depression in Older Adults
Dr. Cohen explains that from the three types of anemia, the type of anemia observed in this trial was primarily iron deficiency anemia, characterized by a shortage of iron in the body, as shared by Johns Hopkins Medicine. Iron is essential for the production of hemoglobin, a substance in red blood cells responsible for oxygen transport. Loss of blood, such as that resulting from GI bleeding, injury, or menstrual bleeding, can contribute to this form of anemia.
According to the Centers for Disease Control and Prevention (CDC), anemia is known to become more prevalent with age, affecting around 10 percent of adults aged 65 and older. The prevalence is even higher among individuals in nursing homes and hospitals, with 39.5 percent of men and 21.9 percent of women aged 85 and older experiencing anemia.
In older adults, anemia has been linked to a range of health issues, including functional decline, increased fatigue, disabilities, depressive symptoms, and cognitive problems, as noted by the National Institute of Health (NIH).
Here are the Current Guidelines for Aspirin
Dr. Cohen goes on to say that the participants in the trial were taking aspirin primarily to prevent heart disease. However, it is also important to note that a daily low-dose aspirin is no longer recommended for primary prevention even if it’s still recommended for secondary prevention.
He says, “But despite that, there are actually still a substantial number of people who are taking aspirin for primary prevention. I think these findings are perhaps another indication of why it might pay to be more cautious in encouraging people to use low-dose aspirin in primary prevention, because here’s yet another potential downside to doing so.”
The primary prevention recommendations are meant to prevent the first occurrence of a heart attack, stroke or cardiovascular disease event. Meanwhile, the secondary prevention of cardiovascular disease is meant to prevent recurrent events in those who have already suffered from a heart attack, stroke, or coronary revascularization procedure, such as a s stint or bypass surgery.
Back in 2022, the U.S. Preventive Services Task Force (USPSTF) recommended against starting low-dose aspirin for the primary prevention of cardiovascular disease in those 60 years old and above. These recommendations were in line with other national organizations, like the American Heart Association (AHA).
This update was based on growing evidence of possible fatal internal bleeding that can result from regular aspirin use, implying that the risks far outweigh the preventive benefits.
The recommendations apply only to the primary prevention group, meaning they don’t apply in any way to those who have already established cardiovascular disease, they clarified in a statement.
This means that experts still agree that you shouldn’t take a daily low-dose aspirin without talking to your doctor. If you do happen to take low-aspirin for secondary prevention of heart disease, do not stop taking it.
The Importance of Speaking With Your Doctor If You Take Daily Aspirin
According to Dr. Cohen, “I think that absolutely, a discussion is warranted about the risks and benefits of taking daily aspirin. In the case of secondary prevention, there is a more substantial weight on the balance side of taking low-dose aspirin, but I think people need to understand that there are still potential downsides as well.”
“In the last few years, primary care doctors have not been recommending daily aspirin as much as they used to. While aspirin is a very important medication for some people, it can cause more harm than benefit in others,” says Dr. McGuirk.
What should one consider when making the decision? Aspirin helps prevent blood clots from forming in the blood vessels, especially in the brain, heart or legs, shares Dr. McGuirk.
She says, “If someone has had a heart attack or stroke before, medications like aspirin are necessary to help prevent it from happening again.”
Aspirin may still be beneficial to those at a higher risk of future heart attack – like smokers, or those with diabetes, or those with an extensive family history of heart disease, explains Dr. McGuirk.
“However, aspirin might not be appropriate in those who have a high risk of bleeding. It is important to talk to your doctor about whether aspirin is right for you. Your doctor can weigh the benefits and risks of aspirin as it relates to your individual health,” she says.
Here are the Recommendations for Older Adults On Daily Aspirin
Dr. McGuirk says, “If someone does need to take daily aspirin, they should talk to their doctor about how to get an iron-rich diet. They should also consider limiting the use of other substances that can irritate the stomach, such as alcohol or NSAIDS, such as ibuprofen or naproxen.”
The current standard of care doesn’t typically involve testing adults for anemia or low iron when there’s no evident cause. However, according to Dr. McGuirk, this recent study prompts consideration of whether individual staking aspirin should undergo periodic blood tests to check for anemia and low iron levels.
“People who are on long-term aspirin should consider asking their doctor if they should be screened for anemia or low iron,” she concludes.
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