Underutilization of clopidogrel and glycoprotein IIb/IIIa inhibitors in non–ST-elevation acute coronary syndrome patients: The Canadian Global Registry of Acute Coronary Events (GRACE) experience

Abstract

There are limited contemporary data on the early use of clopidogrel or glycoprotein (Gp) IIb/IIIa inhibitors, alone versus combination therapies, in non-ST-elevation acute coronary syndrome (NSTE-ACS). This study included 5,806 Canadian NSTE-ACS patients with elevated cardiac biomarker and/or ST deviation on presentation in the prospective GRACE between 2003-2007. We stratified the study population according to the management strategy (non-invasive vs invasive) and into low-(GRACE risk score <or=108), intermediate- (109-140), and high-risk groups (>or=141). Overall, 3,893 patients (67.1%) received early (<or=24 hours of admission) antiplatelet therapy; the rates of use were 76%, 73%, and 57% in the low-, intermediate-, and high-risk groups, respectively (P for trend < .001). Only 54% of the conservatively managed patients and 12% of the invasively managed patients received early clopidogrel and GpIIb/IIIa inhibitors, respectively. High-risk patients were less likely (adjusted odds ratio = 0.48, 95% CI 0.39-0.59, P < .001) to receive early clopidogrel or GpIIb/IIIa inhibitors, whereas in-hospital catheterization was an independent positive predictor (adjusted odds ratio = 2.02, 95% CI 1.74-2.34, P < .001) of use. In this contemporary NSTE-ACS population, both clopidogrel and GpIIb/IIIa inhibitors were targeted toward patients treated with an invasive strategy but paradoxically toward the lower-risk group. In particular, clopidogrel appeared to be underused among conservatively managed patients despite its proven efficacy, whereas GpIIb/IIIa inhibitors were administered to only a minority of the high-risk patients with elevated cardiac biomarkers. Our findings emphasize the ongoing need to promote the optimal use of evidence-based antiplatelet therapies among high-risk patients with NSTE-ACS.