Adults taking low-dose aspirin — whether to prevent recurrent cardiovascular events or to prevent the first event — face an increased risk for CV events if they stop treatment, finds an observational study in Circulation.
Using national Swedish registries, researchers identified over 600,000 adults aged 40 and older who were adherent to aspirin therapy (75–160 mg) for a year. Some 54% were using aspirin to prevent recurrent events (secondary prevention), while the rest were using it to prevent first events (primary prevention).
During roughly 3 years’ follow-up, patients who discontinued aspirin had a 37% increased risk for the composite of myocardial infarction, stroke, or CV death relative to those who adhered to treatment. In the secondary-prevention group, this translated to one additional CV event per year in every 36 patients who stopped aspirin. In the primary-prevention group, this meant one additional CV event per year in every 146 patients who stopped treatment. Risk increased soon after treatment discontinuation and did not seem to lessen over time.