Clinical impact of early clopidogrel discontinuation following acute myocardial infarction hospitalization or stent implantation: analysis in a single integrated health network

Incidence, predictors, and prognosis of premature discontinuation or switch of prasugrel or ticagrelor: the ATLANTIS - SWITCH study

Aim of the present study was to investigate the frequency and predictors of premature discontinuation or switch of ADP receptor blockers and its association with serious adverse events. For this purpose 571 consecutive ACS patients receiving ticagrelor (n = 258, 45%) or prasugrel (n = 313, 55%) undergoing PCI were enrolled in this prospective, observational, multicenter ATLANTIS-SWITCH substudy. Predictors of premature discontinuation or switch of antiplatelet therapy and their association with major adverse cardiovascular events and TIMI bleeding events were evaluated. Premature stop/switch was found in 72 (12.6%) patients: 34 (5.9%) stopped and 38 (6.7%) switched the ADP blocker. Ticagrelor treated patients were significantly more likely to stop/switch therapy as compared to prasugrel (15.9% vs. 9.2%, p = 0.016). We identified 4 independent predictors for stop/switch of ADP blocker: major surgery, need for oral anticoagulation (OAC), TIMI major bleeding and drug intolerance. TIMI major bleeding was a driver of stop/switch actions and occurred in 4.3% vs 0.2% in patients with vs without stop/switch (p = 0.001). The majority of stop/switch actions (75%) were physicians driven decisions. Importantly, stop/switch of therapy was not associated with increased risk of MACE (p = 0.936). In conclusion premature switch/stop of ADP blockers appears to be safe when mainly driven by physician’s decision and clinical indication.

Duration of dual antiplatelet therapy following percutaneous coronary intervention on re-hospitalization for acute coronary syndrome

Background

The optimal duration of dual antiplatelet therapy after percutaneous coronary intervention (PCI) remains uncertain. The objective of this study was to examine the association between duration of dual antiplatelet therapy and re-hospitalization for acute coronary syndrome (ACS) in ACS patients who underwent PCI.

Methods

We identified 975 newly diagnosed ACS patients who underwent PCI between July, 2007 and June, 2009, at a medical center in Taiwan. Cox proportional hazard models were used to examine the association between duration of dual antiplatelet therapy (9 months, 12 months and 15 months) and risks of re-hospitalization for ACS.

Results

At a mean follow-up of 2.3 years, we found that use of clopidogrel for ≥ 12 months was associated with a decreased risk of re-hospitalization for ACS (adjusted HR 0.59, 95% CI 0.36-0.95; p = 0.03). However, use of clopidogrel for ≥ 15 months was not associated with a decreased risk of re-hospitalization for ACS (adjusted HR 0.57, 95% CI 0.29-1.13; p = 0.11). Similar results were found in patients who implanted drug-eluting stents (DES), for whom at least 12 months of clopidogrel therapy is especially critical.

Conclusion

The benefit of ≥ 12 months of clopidogrel use in reducing the risk of re-hospitalization for ACS was significant among ACS patients who underwent PCI and was especially critical for those who implanted DES.

Effect of early clopidogrel discontinuation on rehospitalization in acute coronary syndrome: results from two distinct patient populations

PURPOSE

Results of a study of the association between early discontinuation of clopidogrel therapy and rehospitalization rates among patients with acute coronary syndrome (ACS) are reported.

SUMMARY

In a retrospective observational study, analyses of two nationally representative cohorts of adults hospitalized for acute myocardial infarction (AMI) or coronary stent insertion were conducted to assess risk factors for ACS-related adverse outcomes (rehospitalization for AMI or coronary revascularization) during the 12 months after completion of an initial 28-day course of clopidogrel therapy. Case data were sourced from a commercial insurance claims database, a pharmacy administrative claims database, and a combined dataset that linked hospital discharge and outpatient service data; a time-varying method was used to differentiate adverse events occurring "on" and "off" clopidogrel therapy. One cohort analysis (n = 42,757) indicated that patients who discontinued clopidogrel early (i.e., within 12 months of index discharge) were at significantly increased risk for ACS-related rehospitalization during the 12-month study period (hazard ratio [HR] = 1.11; 95% confidence interval [CI], 1.02-1.20; p < 0.05). In the other cohort analysis (n = 3,171), early clopidogrel discontinuation was associated with an increased risk of rehospitalization or inpatient death (HR = 1.75; 95% CI, 1.59-1.91; p < 0.0001).

CONCLUSION

Observational evidence from analyses of data on two large cohorts of patients with primarily employer-sponsored health insurance suggests that early discontinuation of clopidogrel therapy after hospitalization for AMI or coronary stent insertion is associated with a significant increase in the risk of ACS-related rehospitalization within the 12-month postdischarge period.

Incidence of death and recurring acute coronary syndrome after stopping clopidogrel therapy in a large commercially-insured population in the US

BACKGROUND/OBJECTIVE

Guidelines support clopidogrel therapy in medically-treated or percutaneous coronary intervention (PCI) patients after hospitalization for acute coronary syndrome (ACS). However, clopidogrel discontinuation has been associated with increased short-term risks. This study evaluated the risk of adverse outcomes (AOs), defined as death or recurrent ACS, after clopidogrel discontinuation in a managed-care population.

METHODS

ACS patients (n = 7625) with ≥1 clopidogrel pharmacy claim from 2001 to 2006 and no AO before discontinuing clopidogrel were identified from administrative claims data. AO occurrences were recorded at 90-day intervals following clopidogrel discontinuation.

RESULTS

The mean (SD) duration of clopidogrel therapy for medically-treated, bare metal stent (BMS) and drug eluting stent (DES) patients was 349.2 (393.1) days, 235.6 (383.0) days, and 280.2 (227.1) days, respectively. Among medically-treated patients, Poisson regression analysis showed a 2.19 times higher AO risk (p < 0.01), a 1.63 times greater risk among BMS patients (p < 0.01), and a 1.56 times greater risk for DES patients (p ≥ 0.05) during days 0-90 versus days 91-180 after clopidogrel discontinuation. Sensitivity analysis showed that medically-treated, BMS and DES patients with ≤90 days of clopidogrel therapy had 2.13, 1.68 and 2.40 times higher AO risk, respectively, during days 0-90 versus 91-180 after discontinuation. No significant elevated AO risk was observed after discontinuation in patients on clopidogrel for 91-270 days. Limitations included those associated with the use of administration claims date, the absence of clinical data and lack of knowledge of aspirin use.

CONCLUSIONS

Patients who discontinued clopidogrel therapy were at high risk of death or recurrent ACS during the first 90 days. AO risks following discontinuation appeared elevated in patients with ≤90 days of clopidogrel therapy versus those with >90 days of treatment.

Prevalence of stroke/transient ischemic attack among patients with acute coronary syndromes in a real-world setting

BACKGROUND

Atherothrombosis is a systemic disease that may manifest as acute ischemic events in multiple vascular beds. Patients who have experienced an atherothrombosis-related ischemic event in 1 vascular bed are at risk for developing ischemic events in other vascular beds. Antiplatelet therapy demands an understanding of the balance between arterial thrombosis benefit and adverse event risk. Clinical trials indicate that dual antiplatelet therapy with aspirin and the newer thienopyridines increases the risk of bleeding in patients with acute coronary syndromes (ACS) with prior cerebrovascular events. Informed clinical decision making requires a better understanding of the real-world prevalence of cerebrovascular events.

OBJECTIVE AND PURPOSE

To estimate the prevalence of stroke and/or transient ischemic attack (TIA) among patients with ACS within US health plan populations.

METHODS

A retrospective, observational cohort study was conducted of patients with ACS in 5 health care claims databases. The index event was defined as the first documented inpatient health care claim for myocardial infarction or unstable angina. Patients with ≥12 months of pre-index medical care encounter information were included. Stroke/TIA was identified by the first health care claim for these conditions any time prior to or within 90 days following the index ACS event.

RESULTS

Across all databases, between 3.8% and 15.7% of patients with ACS had prior stroke/TIA and between 3.4% and 11.7% of patients with ACS with no history of cerebrovascular events had documented stroke/TIA following the index ACS hospitalization.

CONCLUSION

Despite important differences between the various database populations, there is a high prevalence of documented stroke/TIA in patients with ACS both prior to and following the ACS event. These real-world findings, set within the context of the increased bleeding risk observed with the newer thienopyridines, are important considerations when selecting antiplatelet therapy for patients with ACS.

Clinical impact of early clopidogrel discontinuation following acute myocardial infarction hospitalization or stent implantation: analysis in a nationally representative managed-care population

OBJECTIVES

To evaluate the association between discontinuation of clopidogrel therapy and risk of acute myocardial infarction (AMI) hospitalization or cardiac revascularization in a nationally-representative patient population following hospitalization for an AMI or coronary stent insertion.

RESEARCH DESIGN AND METHODS

This observational cohort study was performed using data on patients from the PharMetrics Anonymous Patient-Centric Database who were hospitalized for an AMI or coronary stent insertion and subsequently treated with clopidogrel. Cox proportional hazard modeling was used to evaluate the association between clopidogrel discontinuation prior to 1 year post-initial AMI hospitalization and the primary endpoint of repeat AMI hospitalization or coronary intervention defined as percutaneous coronary intervention (PCI) with or without stent, or coronary artery bypass graft (CABG).

MAIN OUTCOME MEASURES

The main outcome for this study was AMI hospitalization or coronary intervention defined as PCI with or without stent placement or CABG.

RESULTS

A total of 31 835 patients were included in the analyses. Patients were predominantly male and the average patient age was approximately 60 years. After controlling for baseline patient characteristics and follow-up time, discontinuation of clopidogrel was associated with a significantly higher rate of hospitalization for AMI or coronary intervention (HR 1.34, 95% CI 1.22-1.44).

CONCLUSION

Within a population of ACS patients drawn from a database of 85 US health plans, clopidogrel discontinuation within 1 year following hospitalization for AMI or stent placement is associated with an increased risk of AMI hospitalization or coronary intervention. The results of this study should be interpreted within the context of observational research, which does not address cause and effect relationships.