Should aspirin be used for the primary prevention of cardiovascular disease in people with diabetes?

To the Editor: The ASPREE (ASPirin in Reducing Events in the Elderly) study may provide useful data on the benefits and risks of aspirin therapy in patients aged ≥ 70 years, as described by Woods and colleagues.1 However, the decision to allow general practitioner co-investigators to “help decide whether the patient is a suitable candidate for the placebo-controlled trial” introduces a source of selection bias that may limit the generalisability of the results. Without pre-specified objective selection criteria, it is likely that primary-prevention patients assessed by GP co-investigators as being at high vascular risk will be excluded because the GPs believe they should be taking antiplatelet agents. Similarly, those at low risk may be thought inappropriate participants because the risks of random allocation to this therapy might outweigh the perceived benefits, as has been shown in previous meta-analyses.2,3 ASPREE may end up with a disproportionate number of intermediate-risk patients.