A recent study suggests that regular low-dose aspirin use may cause anaemia. This article establishes the link between aspirin usage and anaemia along with a piece of advice for patients who regularly consume aspirin.

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Anaemia risk with aspirin use

Anaemia may result from daily low-dose aspirin usage, according to recent research in Annals of Internal Medicine. To obtain these results, researchers examined data from the Aspirin in Reducing Events in the Elderly (ASPREE) trial. In their trial, 19,114 adults aged 70 and older were given a 100 mg aspirin or a placebo at random. The subjects were observed by the researchers for an average of 5 years, during which time their haemoglobin was measured once a year. Ferritin levels were assessed at baseline and three years following randomisation. When your body requires iron, a protein called ferritin in your blood cells releases it.

This new research, which was published in the Annals of Internal Medicine, suggests that those who use a daily low-dose aspirin may be more prone to get anaemia. In persons who were predominantly 70 years of age or older, continued daily aspirin usage raised the incidence of anaemia by 20%.

Importantly, these results were in individuals who showed no signs of gastrointestinal (GI) tract bleeding, which is where one may anticipate aspirin-related bleeding to occur. Even when the anaemia is subclinical, or not severe enough to be clearly visible, it was probably still caused by bleeding. That implies that even in the absence of visible bleeding, those on low-dose aspirin should be watched for the possibility of iron deficits.

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Study results on aspirin and anaemia

A subanalysis of the randomised ASPREE (Aspirin in Reducing Events in the Elderly) trial, which was the first to demonstrate that aspirin did not extend a healthy life span in initially healthy older people, primarily those aged 70 and older, was conducted on data from approximately 18,000 initially healthy older adults in Australia and the United States.

In the group that received 100 mg of aspirin daily for a median of 4.7 years, the incidence of anaemia was 51.2 events per 1,000 person-years, compared to 42.9 occurrences per 1,000 person-years in the placebo group, or those who took a fake tablet in lieu of the aspirin.

In the aspirin group, the predicted likelihood that a participant would get anaemia within five years was 23.5 per cent, as opposed to 20.3 per cent in the placebo group.

Additionally, aspirin users were more likely to encounter a clinically significant bleeding episode; in the aspirin group, 3% of participants had at least one incident, as opposed to 2% in the placebo group.

Researchers found the following when compared to subjects receiving a placebo:

1. Those who regularly use aspirin have a 20% increased chance of getting anaemia.
2. The mean haemoglobin of individuals receiving aspirin slightly decreased.
3. The quantities of ferritin decreased more noticeably.

According to their findings, anyone using daily aspirin should have their ferritin and iron levels routinely checked. The research features a large participant pool overall, which increases its significance and reliability. The conclusions are additionally strengthened by the fact that this research was conducted in two separate nations.

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Researchers uncover 'hidden' blood loss after daily aspirin use

This is the first extensive investigation of aspirin's long-term adverse effects. Although we already know that aspirin may sometimes lead to major bleeding issues requiring hospitalisation, this research demonstrates that aspirin users may also have 'hidden' blood loss. People who use aspirin over time may have modest quantities of blood loss in their stool due to stomach discomfort.

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What are current recommendations regarding aspirin?

1. The U.S. Preventive Services Task Force advised against aspirin use in persons 60 and older to prevent cardiovascular disease in April 2022.
2. According to the task group, aspirin should be taken into account on an individual basis for adults aged 40 to 59 who have an estimated cardiovascular risk of 10% or higher.

While it should be mentioned that daily low-dose aspirin is no longer advised for primary prevention, it is still advised for secondary prevention, the participants in this experiment were taking aspirin for the primary prevention of heart disease.

In spite of this, a significant portion of individuals continue to use aspirin as a main preventative. These results may serve as yet another reason to be extra careful when advising patients to take low-dose aspirin for primary prevention, since there may still be another drawback.

While secondary prevention of cardiovascular disease is meant to prevent recurrent events in people who have already had a heart attack, stroke, or coronary revascularisation procedure (like a stent or a bypass surgery), primary prevention recommendations are meant to prevent the first occurrence of a heart attack, stroke, or a cardiovascular disease event.

In accordance with other national organisations like the American Heart Association (AHA), the U.S. Preventive Services Task Force (USPSTF) advised against initiating low-dose aspirin for the primary prevention of cardiovascular disease in adults 60 or older in 2022.

The modification was made in response to growing evidence that frequent aspirin usage might cause internal bleeding that can be deadly, indicating that the dangers may outweigh the preventative advantages.

According to the statement, the guidelines only apply to those who are in the main preventive category and have no bearing on those who already have developed cardiovascular disease.

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Recognising the connection between aspirin usage and anaemia

The increased risk of gastrointestinal bleeding is largely responsible for the link between aspirin usage and anaemia in older persons. Since iron is required to create haemoglobin in red blood cells, chronic or repeated gastrointestinal bleeding may result in iron deficiency anaemia. Chronic blood loss may deplete the body's iron reserves, eventually leading to anaemia.

The risk of developing anaemia in older persons who use aspirin varies based on a number of variables, including the person's general health, the dosage and length of aspirin usage, and any other underlying illnesses they may have. As well as protective medicine to stop bleeding when aspirin or other NSAID drugs are taken, there are substitute treatments that may have a reduced risk of gastrointestinal bleeding. The choice of which medicine, if any, to take requires an informed assessment of the advantages and disadvantages, as well as careful consideration of all available options.

Depending on the disease for which aspirin is being administered, there may be alternatives. Aspirin is often used to treat pain, and inflammation, and to prevent blood clotting, which may cause heart attacks and strokes. An alternate pain reliever is acetaminophen. An alternate NSAID anti-inflammatory is ibuprofen. A clot-preventing antiplatelet medication is a clopidogrel.

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Additional possible issues

When taking aspirin regularly, the anticoagulant drugs Xarelto and Eliquis, which are used to treat atrial fibrillation and blood clots, may significantly increase the risk of bleeding.

Other possible side effects include, of course, bleeding, stomach discomfort, abdominal ulcers, dehydration, nausea, vomiting, rash/hives (if allergic response), bruises, a higher risk of brain bleeds in patients with head injuries, renal and liver problems, and so on.

Aspirin does have certain useful use, however. Some medical professionals advise patients to take low-dose aspirin rather than forego treatment and worry about anaemia concerns in order to avoid additional cardiovascular issues. Today's aspirin tablets are "enteric" coated, which means they can resist the stomach acid that is produced before they are completely dissolved in the small intestine. This may provide further defence against stomach/gastrointestinal bleeding.

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Advice for seniors who take aspirin daily

If someone must take aspirin every day, they should discuss a diet high in iron with their doctor. They should also think about reducing their intake of other drugs like alcohol or NSAIDs like ibuprofen and naproxen that might irritate the stomach.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Monish Raut is a practising super specialist from New Delhi.