December 4, 2019

expert reaction to study looking at aspirin use and mortality in older adults

Research, published in JAMA Network Open, reports that regular aspirin use may reduce risk of mortality among older individuals.

Prof Stephen Evans, Professor of Pharmacoepidemiology, London School of Hygiene & Tropical Medicine, said:

“This paper describes some results from a large study.  It shows convincingly that those who were on aspirin when starting a trial of cancer screening had different mortality and cancer risks in the succeeding years.  It is not at all certain whether this difference was due to their taking aspirin or to other factors.  The participants had themselves chosen to use aspirin, and it is highly likely that they were on average healthier than those who did not use aspirin.

“It is almost misleading to emphasise the word ‘trial’ for these results, since aspirin use was not part of the trial of screening.  It is not a randomised trial of aspirin use in the elderly, and although the authors seem to regard its results as providing evidence against the findings of the ASPREE study which found increased bleeding in those randomly allocated to aspirin which led to an overall increase in mortality, this is essentially an observational study which cannot simply overturn those findings.  This observational study adds to the evidence that aspirin is beneficial in reducing colo-rectal cancer which has been shown in randomised and observational studies, but its severe limitations mean that the other results are not reliable.  The authors note the likelihood of ‘unmeasured confounding’ being an explanation for at least some of their results.  This is saying that the aspirin users differed from non-users in ways that affected their risk of mortality and other illnesses such as cancer.

“The study does not provide sufficient evidence to recommend daily aspirin use as offering overall health benefits in the elderly who do not have elevated risks of heart disease.”

‘Association of aspirin use with mortality risk among older adult participants in the prostate, lung, colorectal, and ovarian cancer screening trial’ by Holli A. Loomans-Kropp et al. was published in JAMA Network Open at 16:00 UK time on Wednesday 4 December 2019. 

DOI: 10.1001/jamanetworkopen.2019.16729

Declared interests

Prof Stephen Evans: “No conflicts of interest.”