Daily Low-Dose Aspirin and Risk of Serious Falls and Fractures in Healthy Older People: A Substudy of the ASPREE Randomized Clinical Trial

ImportanceFalls and fractures are frequent and deleterious to the health of older people. Aspirin has been reported to reduce bone fragility and slow bone loss.ObjectiveTo determine if daily low-dose aspirin (100 mg) reduces the risk of fractures or serious falls (fall-related hospital presentations) in healthy older men and women.Design, Setting, and ParticipantsThis substudy of a double-blind, randomized, placebo-controlled trial studied older adult men and women in 16 major sites across southeastern Australia. The ASPREE-FRACTURE substudy was conducted as part of the Australian component of the ASPREE trial. Between 2010 and 2014 healthy (free of cardiovascular disease, dementia or physical disability), community-dwelling volunteers aged 70 years or older were recruited to participate in the ASPREE trial. Potentially eligible participants were identified by medical practitioners and trial personnel and were then sent a letter of invitation to participate. Interested participants were screened for suitability. Eligible participants with medical practitioner authorization and adherent to a 4-week run-in medication trial were randomized. Data were analyzed from October 17, 2019, to August 31, 2022.InterventionsParticipants in the intervention group received a daily dose of oral 100 mg enteric-coated (low-dose) aspirin. The control group received a daily identical enteric-coated placebo tablet.Main Outcomes and MeasuresThe primary outcome of ASPREE-FRACTURE was the occurrence of any fracture. The secondary outcome was serious fall resulting in hospital presentation.ResultsIn total, 16 703 people with a median (IQR) age of 74 (72-78) years were recruited, and 9179 (55.0%) were women. There were 8322 intervention participants and 8381 control participants included in the primary and secondary outcome analysis of 2865 fractures and 1688 serious falls over the median follow-up of 4.6 years. While there was no difference in the risk of first fracture between the intervention and control participants (hazard ratio, 0.97; 95% CI, 0.87-1.06; P = .50), aspirin was associated with a higher risk of serious falls (total falls 884 vs 804; incidence rate ratio, 1.17; 95% CI, 1.03-1.33; P = .01). Results remained unchanged in analyses that adjusted for covariates known to influence fracture and fall risk.Conclusions and RelevanceIn this substudy of a randomized clinical trial, the failure of low-dose aspirin to reduce the risk of fractures while increasing the risk of serious falls adds to evidence that this agent provides little favorable benefit in a healthy, White older adult population.Trial RegistrationThis substudy is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615000347561).