A daily low dose of aspirin won’t help healthy older people stay alive any longer, suggests new research published this week in The New England Journal of Medicine. It might even raise their risk of dying early of certain things, such as cancer.
The disappointing findings come from an extensive, randomised and controlled study that first began in 2010, known as the ASPirin in Reducing Events in the Elderly (ASPREE) trial.
Over the next four years, nearly 20,000 people mostly over the age of 70 in both Australia and the US were recruited for the trial. Black and Hispanic volunteers between 65 and 70 were included as well, since these groups have a higher risk of heart disease and dementia. All of the volunteers had no history of cardiovascular disease, dementia or other major health problems.
Half of them were asked to take 100mg of aspirin a day, while the other half took a placebo.
The trial was scheduled to conclude at the end of 2017, but it was ended six months early, in June, because the results were already clear. After a median length of 4.7 years, the team found, people who took aspirin were just as likely to die than those who took a placebo. Specifically, 9.7 per cent of the aspirin group had died of any cause, compared to 9.5 per cent of the placebo group.
Other studies have long shown that aspirin use can help prevent heart attacks and stroke in people who already have heart disease. But there’s been a more contentious debate about whether preventative aspirin could help relatively healthy people avoid heart problems.
“This study shows why it is so important to conduct this type of research, so that we can gain a fuller picture of aspirin’s benefits and risks among healthy older persons,” Richard Hodes, director of the National Institute of Ageing, which helped fund the trial, said in a statement.
The lack of any positive benefit wasn’t the only major finding from the ASPREE trial. Aspirin is known to increase the risk of bleeding. And in a separate paper, the authors reported that people who took daily aspirin were more likely to have an episode of major bleeding: 3.8 per cent of aspirin-takers had a major haemorrhage, compared to 2.8 per cent of people on placebo.
But less expected was the effect the drug seemed to have on cancer death rates. In a third paper, they reported that 3.1 per cent of people died from cancer in the aspirin group, compared to 2.3 per cent of people in the placebo group. These extra cancer deaths explained the slightly higher mortality rate seen overall in the aspirin group.
At this point, though, it’s unclear whether this finding actually means something. There were fewer than 600 cancer-related deaths in total, with only 66 deaths separating the two groups. So it’s possible the results could be chance. It also flies in the face of other major research showing that aspirin can prevent cancer, particularly in the colon and gut.
“Analysis of all the cancer-related data from the trial is under way and until we have additional data, these findings should be interpreted with caution,” said Leslie Ford, associate director for clinical research at the National Cancer Institute’s Division of Cancer Prevention.
The ASPREE trial is unlikely to be the final word on whether preventative aspirin is worthwhile. Aspirin might still help some middle-aged people younger than 65, or it could have longer-reaching benefits for the elderly that would take more years to pay off, such as preventing dementia (in the current study, though, there was no difference in the dementia rate).
As the authors themselves point out, the study doesn’t “directly address the question of whether healthy older persons who have been using aspirin for primary prevention should continue or discontinue its use”.
They plan to continue analysing data from the ASPREE trial, and hope to keep track of their volunteers in the years to come.