Aims: Current guidelines recommend the use of dual antiplatelet therapy (DAT) (aspirin+clopidogrel) for patients after acute myocardial infarction (MI). In relation to this, we sought to examine the adherence to this recommended treatment regimen in a population of patients admitted with MI and subsequent percutaneous coronary intervention (PCI).
Methods and results: A cohort study was conducted using data from the main health insurance reimbursement database of South West France. Patients hospitalised for MI in 2008 were identified, and then their reimbursement form of DAT for the subsequent 12 months was reviewed. Adherence was assessed by using the proportion of days covered by the treatment and persistence. Among the 634 patients included in the study, 34 had no reimbursement for DAT immediately after discharge. For the remaining patients, the probability of stopping DAT at least for one month was 18.6% (95% CI [15.4;21.8]) during the first three months and 49.1% (95% CI [44.9;53.2]) at 12 months, although the medication availability was 90%.
Conclusions: These results suggest that while this medication is available to patients, the treatment is often stopped before one year. This may account for what has been reported as "resistance" to antiplatelet therapy described in a subset of patients.