Clopidogrel and aspirin versus aspirin alone for the prevention of atherothrombotic events

Dual antiplatelet therapy with clopidogrel plus low-dose aspirin has not been studied in a broad population of patients at high risk for atherothrombotic events

Aspirin to prevent cardiovascular disease : The association of aspirin dose and clopidogrel with thrombosis and bleeding

Background: The optimal aspirin dose for the prevention of cardiovascular events remains controversial. Objective: To assess the incidence of and risk factors for adverse clinical outcomes by investigator-determined aspirin dose in a primary prevention trial. Design: Post hoc observational analyses of data from a double-blind, placebo-controlled, randomized trial. Setting: Outpatient. Patients: 15 595 patients with cardiovascular disease or multiple risk factors. Intervention: Clopidogrel, 75 mg/d, or placebo, with aspirin, 75 to 162 mg/d, as selected by the investigators. Measurements: Incidence of the composite outcome of myocardial infarction, stroke, or cardiovascular death (efficacy end point), and incidence of severe or life-threatening bleeding (safety end point), at a median of 28 months (interquartile range, 23 to 31 months) of follow-up. Results: Daily aspirin doses were categorized as less than 100 mg (75 or 81 mg) (n = 7180), 100 mg (n = 4961), and greater than 100 mg (150 or 162 mg) (n = 3454). The hazard of the primary efficacy end point was the same regardless of dose (adjusted hazard ratio, 0.95 [95% CI, 0.80 to 1.13] for 100 mg vs. less than 100 mg, and 1.0 [CI, 0.85 to 1.18] for greater than 100 mg vs. less than 100 mg). The hazard of the primary safety end point also did not depend on dose (adjusted hazard ratio, 0.85 [CI, 0.57 to 1.26] for 100 mg vs. less than 100 mg and 1.05 [CI, 0.74 to 1.48] for greater than 100 mg vs. less than 100 mg). In patients also receiving clopidogrel, daily aspirin doses greater than 100 mg seemed to be non–statistically significantly associated with reduced efficacy (adjusted hazard ratio, 1.16 [CI, 0.93 to 1.44]) and increased harm (adjusted hazard ratio, 1.30 [CI, 0.83 to 2.04]). Limitation: The analysis was post hoc, and aspirin use was not randomized or blinded. Conclusion: Daily aspirin doses of 100 mg or greater were associated with no clear benefit in patients taking aspirin only and possibly with harm in patients taking clopidogrel. Daily doses of 75 to 81 mg may optimize efficacy and safety for patients requiring aspirin for long-term prevention, especially for those receiving dual antiplatelet therapy. Steven R. Steinhubl, MD; Deepak L. Bhatt, MD, MPH; Danielle M. Brennan, MS; Gilles Montalescot, MD; Graeme J. Hankey, MD; John W. Eikelboom, MB, BS, MSc; Peter B. Berger, MD; Eric J. Topol, MD; and on behalf of the CHARISMA Investigator

Smoking, clopidogrel, and mortality in patients with established cardiovascular disease

BACKGROUND: Smoking increases platelet aggregability, and the degree of platelet inhibition by clopidogrel on ex vivo platelet function tests. Whether smoking status affects the relationship between clopidogrel and clinical outcomes is unknown. METHODS AND RESULTS: We evaluated the relationship between smoking status (current smoker (CS), former smoker (FS), and never smoker (NS)) and treatment with clopidogrel on the risk of all-cause, cardiovascular, and cancer mortality among the 12,152 participants from the CHARISMA trial with established cardiovascular disease. Current smoking was associated with an increase in all-cause (adjusted hazard ratio [HR] 2.58, [1.85–3.60]), cardiovascular (HR 2.26, [1.48–3.45]), and cancer mortality (HR 4.16, [2.46–7.03]) compared to NS. The impact of clopidogrel and mortality differed by smoking status (P for interaction = 0.018 for current smokers). Among CS, clopidogrel was associated with a reduction in all-cause mortality (HR 0.68, [0.49–0.94]); clopidogrel did not reduce all cause mortality among FS (HR 0.95, [0.75–1.19]) or NS (HR 1.14, [0.83–1.58]). A similar pattern was noted for cardiovascular mortality. As expected, no relationship was observed between clopidogrel and cancer mortality by smoking status. The risk of bleeding seemed to differ according to smoking status; randomized clopidogrel was associated with a significantly increased hazard of severe or moderate bleeding (HR 1.62, P=0.04) among CS, but a smaller and nonsignificant increase among NS (HR 1.31, P=0.15). CONCLUSION: Clopidogrel therapy may be more effective, but with a greater bleeding risk in CS than in patients who are not smokers. Further studies are needed to investigate this possibility

Expert consensus document on the use of antiplatelet agents: 2010 update.

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Clinical outcomes of patients with diabetic nephropathy randomized to clopidogrel plus aspirin versus aspirin alone (A post hoc analysis of the clopidogrel for high atherothrombotic risk and ischemic stabilization, management, and avoidance [CHARISMA] Tri

No prospective randomized trial has specifically examined the long-term outcomes of clopidogrel use in patients with chronic kidney disease. This study aimed to determine the risks and benefits of long-term clopidogrel administration in patients with diabetic nephropathy, the most common form of chronic kidney disease. We performed a post hoc analysis of the CHARISMA trial, which randomly assigned patients without active acute coronary syndrome, but with established atherosclerotic disease (symptomatic) or multiple risk factors for atherosclerotic disease (asymptomatic), to clopidogrel plus aspirin versus placebo plus aspirin. All CHARISMA patients (n = 15,603) were separated into the 3 groups: nondiabetic patients, diabetic patients without nephropathy, and diabetic patients with nephropathy. Within each group, outcomes of patients randomly assigned to clopidogrel were compared with those of patients randomly assigned to placebo. Outcomes in the prespecified CHARISMA subgroups of asymptomatic and symptomatic patients were also compared with respect to study drug assignment and nephropathy status. Patients with nephropathy who received clopidogrel had no difference in bleeding, but experienced significantly increased cardiovascular (CV) and overall mortality compared with those randomly assigned to placebo. There were no differences in bleeding, overall mortality, or CV mortality for nondiabetic or diabetic patients without nephropathy who received clopidogrel versus placebo. In the asymptomatic cohort, patients with nephropathy randomly assigned to clopidogrel had significantly increased overall and CV mortality compared with placebo, whereas asymptomatic patients without nephropathy randomly assigned to clopidogrel had no significant mortality difference compared with placebo. In conclusion, this post hoc analysis suggested that clopidogrel may be harmful in patients with diabetic nephropathy. Additional studies are needed to investigate this possible interaction

An analysis of mortality rates with dual-antiplatelet therapy in the primary prevention population of the CHARISMA trial

To examine the unanticipated, excess mortality observed in patients randomized to clopidogrel and aspirin vs. aspirin alone in the prespecified 'asymptomatic' subgroup of CHARISMA, we investigated whether dual-antiplatelet therapy may be associated with adverse cardiovascular (CV) events in a primary prevention population