The characteristics of patients with a recent history of acute myocardial infarction and their antiplatelet therapy utilization pattern in the UK general practice

Abstract

Purpose: Patients with a recent history of acute myocardial infraction (MI) are at an increased risk for subsequent cardiovascular (CV) events. Dual antiplatelet therapy (DAT) of aspirin and P2Y12 antagonists such as clopidogrel, prasugrel, and ticagrelor are recommended by ESC guidelines (2012) for secondary prevention of CV events, especially in the first year post MI. This analysis assessed among patients in a UK general practice setting, their characteristics and utilization pattern of antiplatelet therapy following an MI. Methods: Using a UK general practice database, patients who had an acute MI event between 12/01/2009 and 11/30/2010 (index period) and aged ≥18 years at the time of MI were identified and retrospectively followed up for 2 years (up to 11/30/2012). The last MI event during the index period is classified as the index MI. Those patients with a history of any stroke or transient ischemic attack (TIA) prior to the index MI were excluded, due to heightened bleeding risk and contraindications to certain combination antiplatelet treatment. All selected patients had available medical records for at least 1 year prior to and 2 years following the index MI. MI, stroke and TIA history were evaluated through all the available medical records prior to the index MI. Other patient characteristics were assessed according to the records 1 year prior to the index MI. The aspirin and P2Y12 antagonists use was based on the prescription records of 1 year prior to and 2 years post index MI. Results: Among 5,422 patients (71% males, mean age 69 years [SD 12]) who met the selection criteria, 66% were <75 years of age, 86% weighed ≥ 60 kg; 87% had a history of prior MI, 18% had other ischemic heart disease, 20% had diabetes, 34% had hypertension, 1% had peripheral artery disease, and 83% were on statin. Prior to the index MI, 71% of patients received aspirin and 15% received DAT with 99.7% of P2Y12 antagonist prescriptions being clopidogrel. In the first and second years following the index MI, 78% and 74% of patients received aspirin, only 20% and 10% received DAT, with 97% and 96% of P2Y12 antagonist prescriptions being clopidogrel, respectively. Conclusions: In a UK general practice setting, patients with acute MI were more likely to have multiple CV risk factors and many had previously experienced an MI. Despite a high risk for recurrent MI in these patients, the prescription of a P2Y12 antagonist (mostly clopidogrel) was unexpectedly low, in contrast to the current ESC recommendations.