Dispensing data captures individual-level use of aspirin for cardiovascular disease prevention, despite availability over-the-counter
Vanessa Selak, Yulong Gu, Natasha Rafter, Sue Crengle, Andrew Kerr, Chris Bullen
The use of triple therapy (aspirin/antiplatelet, blood pressure-lowering and statin medication) is monitored as a national quality indicator in New Zealand among people who have had a cardiovascular event (eg, heart attack or stroke), for whom all three medications are recommended. Monitoring is undertaken using national pharmaceutical dispensing data, but because aspirin is available over-the-counter (ie, without being prescribed by a doctor and dispensed by a pharmacist), dispensing data may underestimate aspirin use. We compared aspirin medication use measured by self-report and dispensing data among New Zealand patients for whom triple therapy was recommended by their general practitioner, and found that the level of agreement between these two measures was comparable to that for blood pressure-lowering and statin medication, which are not available over-the-counter. We conclude that in New Zealand, aspirin dispensing is a valid source of data for the use of this medication among patients with cardiovascular indications, despite its availability over-the-counter.