Healthy elderly people who take a daily ‘child aspirin’ to keep their heart and blood vessels healthy run a 20 percent higher risk of anemia. Australian researchers have found this in a new study that has been published in the medical journal Annals of Internal Medicine. They recommend that doctors regularly check the blood of people over 70 who take such a low daily dose of aspirin.
Aspirin (acetylsalicylic acid) is a classic and widely used remedy for pain and fever, but in lower doses it also works as a blood thinner. It prevents clots from forming in the blood, which can block arteries and cause a heart attack or stroke, for example. A daily low-dose aspirin helps prevent new problems in people with cardiovascular disease, a series of previous studies have shown. This led to the idea around the turn of the century that a preventive ‘child aspirin’ would also be a good idea for healthy people, to keep their heart and blood vessels healthy.
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In the United States, half of the elderly take low-dose aspirin, between 50 and 100 mg, as a preventive measure. In the Netherlands, acetylsalicylic acid is still one of the five most commonly dispensed drugs at the pharmacy to lower the risk of cardiovascular disease. It is not known how many people take it preventively.
19,000 people over seventy
In the new study, the researchers reanalyzed data from a large study of more than 19,000 people over the age of seventy in Australia and the United States, the Aspree study. Half of those participants received a daily 100 milligram aspirin, the other half did not. The participants did not know which pill they received, they were followed for almost five years.
Read about the big study: Aspirin bad for healthy senior
That study already showed in 2018 that a daily low dose of aspirin hardly prevents cardiovascular disease, but does increase the risk of serious bleeding. Partly because of this, the guidelines for use have been adjusted internationally.
In the new study, the researchers did not focus on bleeding, but on anemia. This is common in the elderly, who feel tired, weak and short of breath as a result. Due to a shortage of red blood cells, the body cannot absorb enough oxygen.
The concentration of the protein hemoglobin in the blood of the Aspree participants was measured annually, a measure of the red blood cells. The amount of iron (ferritin) in the blood was measured at the start of the study and after three years. Low iron and hemoglobin levels indicate anemia.
Aspirin is not recommended for healthy people without cardiovascular disease
The risk of anemia was 23.5 percent for the aspirin takers, a fifth higher than for the people who had taken a dummy pill. The concentration of hemoglobin and iron in the blood was also lower in the people who received aspirin. That difference could not be explained by bleeding that had occurred. The authors suspect that unnoticed bleeding causes the anemia.
In the Netherlands, low-dose aspirin is only prescribed to people who are at increased risk of blood clots, such as after a stroke or heart attack, says Jako Burgers, general practitioner in Gorinchem and professor of person-centered care in guidelines at Maastricht University. “In the guidelines for general practitioners, aspirin is not recommended for healthy people without cardiovascular disease. Only for people with a history of cardiovascular disease does the risk of side effects outweigh the risks of their condition.” For healthy people it is the other way around. It is therefore better not to take a preventive aspirin.