Aspirin and anaemia risk in older adults

Jun 21, 2023

Low-dose aspirin may increase anaemia risk in healthy older adults: study


A new study analysing data from the landmark ASPREE trial has found that prolonged daily aspirin use increases the risk of anaemia by 20% in some older adults, mostly aged 70 years or more.

Findings from ASPREE-Anaemia, a sub-study of the ASPREE trial, may help GPs identify older patients at higher risk of anaemia and who may benefit from regular monitoring for development of the condition.

Above: Prof Zoe McQuilten, lead author of the aspirin and anaemia sub-study.

Anaemia is commonly experienced by older adults, potentially affecting overall function and increasing fatigue, disabilities, depressive symptoms and problems with thinking and memory. Around one third of all cases of anaemia in older adults have no known cause.

The study, published in Annals of Internal Medicine, followed 18,153 initially healthy older adults in the USA and Australia and recorded incidents of anaemia over an average 4.7 years.

The risk of developing anaemia was found to be 20 per cent higher in the aspirin group compared to those in the placebo group.

In addition to a higher risk of anaemia, blood tests revealed a faster decline of haemoglobin (a protein that carries oxygen in our red blood cells) and reduced ferritin (a protein that carries iron) levels in the aspirin group compared to the placebo group.

This is the largest investigation into anaemia in older people and was part of the randomised controlled trial, ASPREE (ASPirin in Reducing Events in the Elderly) – with half the participants taking a placebo and the other half a daily low dose (100mg) of aspirin.

Over the duration of the trial, 18% of participants in the aspirin group and 15% in the placebo group developed anaemia.

Lead author, Professor Zoe McQuilten from Monash University’s School of Public Health and Preventive Medicine, said while bleeding was a known side-effect of aspirin, few previous studies had looked at the effect of prolonged aspirin use on the progressive development of anaemia in older adults: “The ASPREE-Anaemia sub-study gives a clearer picture of the additional risk of becoming anaemic with aspirin use and the impact is likely to be greater in older adults with underlying diseases, such as kidney disease.”

Prof McQuilten said the new data gave GPs insight into the risk of anaemia from prolonged aspirin use by their older patients. “Older adults are more likely to become anaemic generally, and now doctors can potentially identify patients at higher risk of developing anaemia,” she said.

Prof McQuilten urged patients to follow the advice of their doctor about their daily use of aspirin. She cautioned that for some older adults, aspirin was recommended as a valuable therapy to prevent recurring heart attacks or stroke. “Patients should not change their aspirin regimen without speaking to their doctor,” she said.

“GPs are experienced at investigating and managing anaemia and low iron levels.”

In Australia, ferritin levels were measured using blood samples donated to the ASPREE Biobank.

ASPREE was primarily funded by the National Institutes of Health in the USA, Victorian Cancer Agency, Monash University and the NHMRC in Australia. The ASPREE-Anaemia sub-study was funded in part by the Alfred Health Research Trust.

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