ASPREE: Stopping aspirin does not appear to benefit or harm older adults
In a post hoc subgroup analysis of the ASPREE trial, those taking aspirin before the trial who were assigned placebo did not experience serious benefits or harms, researchers reported.
As Healio previously reported, in the main results of ASPREE, among adults aged at least 70 years with no history of CVD, aspirin did not reduce CVD risk and was associated with elevated risk for major hemorrhage compared with placebo.
For the present analysis, Mark R. Nelson, MBBS(Hons), MFM, PhD, head of Discipline of General Practice at Menzies Institute for Medical Research, University of Tasmania in Australia, and honorary associate at Monash University, Melbourne, and colleagues analyzed 1,714 participants from ASPREE who reported taking aspirin at least 2 days per week before enrollment. The cohort consisted of 40.6% Americans, larger than the percentage in the overall cohort (12.6%).
Among those taking aspirin at least 2 days per week before enrollment, there was no significant difference in the primary outcome of all-cause mortality, dementia or persistent disability between those assigned aspirin and those assigned placebo at a median of 4.9 years (placebo group, 13.8%; incidence rate, 29.8 per 1,000 person-years; aspirin group, 11.1%; incidence rate, 23.4 per 1,000 person-years; HR = 1.28; 95% CI, 0.98-1.68), according to the researchers.
Risk for CV events did not differ between the groups (HR = 1.32; 95% CI, 0.89-1.97), but in those who had been taking aspirin at least 5 years before enrollment, assignment to the placebo group was associated with elevated risk for CV events (HR = 2.08; 95% CI, 1.11-3.9), Nelson and colleagues wrote.
There was no difference between the groups in major bleeding events (HR = 0.92; 95% CI, 0.55-1.53) or cancer (HR = 0.88; 95% CI, 0.66-1.18), the researchers wrote.
“Noting that the analyses are likely underpowered, our findings cannot conclusively demonstrate clear harm or benefit of either cessation or continuation of aspirin in older adults,” Nelson and colleagues wrote.
In a related editorial, Ella Murphy, MB BCh BAO, MSc, and John W. (“Bill”) McEvoy, MB BCh BAO, MEd, MHS, both from University Hospital Galway, Saolta University Health Care Group and National University of Ireland Galway, wrote: “While the analysis presented by Nelson and colleagues is timely and important, and the results interesting, they should be interpreted with the limitations of a post hoc subgroup analysis in mind. Replication is needed. Though the data are inconsistent, rebound platelet reactivity may occur on aspirin cessation, so there could be a biologically plausible mechanism to explain increased CVD risk (whether that be transient or more sustained) among persons receiving chronic aspirin who then stop.”