In-Hospital Switching Between Clopidogrel and Prasugrel Among Patients With Acute Myocardial Infarction Treated With Percutaneous Coronary Intervention: Insights Into Contemporary Practice From the National Cardiovascular Data Registry

Background—Although randomized clinical trials have compared clopidogrel with higher potency ADP receptor inhibitors (ADPris) among patients with myocardial infarction, little is known about the frequency and factors associated with switching between ADPris in clinical practice. Methods and Results—We studied 47 040 patients with myocardial infarction treated with percutaneous coronary intervention, who received either clopidogrel or prasugrel within 24 hours of admission at 361 US hospitals from July 2009 to June 2011 using the merged Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With the Guidelines and CathPCI Registry database. Hierarchical logistic regression modeling was used to determine factors independently associated with in-hospital ADPri switching. Among 40 531 patients treated initially in-hospital with clopidogrel, 2125 (5.2%) were discharged on prasugrel; this frequency steadily increased from 0% to 7% during the study period. Among 6509 patients treated initially in-hospital with prasugrel, 751 (11.5%) were discharged on clopidogrel. The frequency of this switch increased from 6% to 18% during the first 2 quarters of the study period and decreased to 9% by the end. Switching clopidogrel to prasugrel was associated with high-risk angiographic characteristics (thrombotic, long, and bifurcating lesions), reinfarction in-hospital, and private health insurance coverage. Older age, previous cerebrovascular event, in-hospital coronary artery bypass grafting, in-hospital bleeding, and warfarin use at discharge were associated with switching prasugrel to clopidogrel. Conclusions—Clopidogrel and prasugrel are not uncommonly switched in-hospital in patients with myocardial infarction undergoing percutaneous coronary intervention. In contemporary US practice, in addition to risk for bleeding and recurrent ischemic events, medical drug coverage is a major determinant of ADPri selection.