People who take daily low-dose aspirin to ward off illness in old age are unlikely to benefit from the drug, a large clinical trial has found.
People who have previously experienced heart attacks, strokes, and angina, a daily dose of the blood-thinning medicine protect them in older age, but researchers found the drug did not extend the lifespan of people over 70-years.
A population of about 19,000 healthy people aged over 70 participates in the trail. Initial findings were published in three papers in the New England Journal of Medicine.
Half the group was asked to take 100mg of low-dose aspirin per day, while the rest took a placebo pill.
Five years later, among the group assigned to take aspirin, 90.3 percent remained alive at the end of the treatment without persistent physical disability or dementia, compared with 90.5 percent of those taking a placebo. Rates of physical disability were similar, and rates of dementia were almost identical in both groups.
Moreover, the group taking aspirin had an increased risk of death compared to the placebo group: 5.9 percent of participants taking aspirin and 5.2 percent taking placebo died during the study.
The investigators noted that the drug was associated with a significantly increased risk of bleeding. The Aspirin group experienced more internal bleeding, with 3.8 percent of them having serious medical conditions ranging from brain stroke to gastrointestinal bleeds, compared with 2.7 percent in the placebo group.
This effect has not been noted in previous studies. The higher death rate in the aspirin-treated group was due primarily to a higher rate of cancer deaths. A small increase in new cancer cases was reported in the group taking aspirin but the difference could have been due to chance.
The researchers also found that the rates for major cardiovascular events–including coronary heart disease, nonfatal heart attacks, and fatal and nonfatal ischemic stroke–were similar in the aspirin and the placebo groups.
“The increase in cancer deaths in study participants was surprising, given prior studies suggesting aspirin use improved cancer outcomes,” said Leslie Ford, M.D., associate director for clinical research. “Analysis of all the cancer-related data from the trial is underway, and until we have additional data, these findings should be interpreted with caution.”
Evan Hadley, M.D., director of NIA’s Division of Geriatrics and Clinical Gerontology said: “Continuing follow-up of the participants is crucial, particularly since longer-term effects on risks for outcomes such as cancer and dementia may differ from those during the study to date.”