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Long-term clinical outcome of aspirin vs clopidogrel monotherapy in patients with post percutaneous coronary intervention (PCI): Host-Exam extended study

Key Takeaway

The findings from Host-Exam Extended study in patients with CAD showed that during an extended median follow-up of 5.8 years after randomization, clopidogrel monotherapy vs aspirin monotherapy was associated with:

  • Lower discontinuation rate (8% vs 13.5%; P <0.001), indicating stronger clopidogrel treatment adherence
  • Significant Reduction (P <0.001) in the risk of composite of all-cause death,non-fatal MI, stroke, readmission due to ACS, and BARC type ≥3 bleeding
  • Lowered risk of thrombotic, (P <0.001) and any bleeding (BARC type ≥2, P = 0.016);
    • No significant difference in the risk of all-cause death
  • Consistent treatment effects across subgroups with no significant interaction
  • Long-term treatment with clopidogrel monotherapy caused consistent reduction in CV events vs aspirin monotherapy.
  • The Host-Exam extended study supported use of clopidogrel as the preferable antiplatelet agent for secondary prevention of CAD.

Why this Matters

  • Antiplatelet therapy is an integral component for secondary prevention of atherothrombotic CV events,after PCI.
  • Longer term follow-up studywas required to provide clarification to the contradicting findings of Host-Exam trial at rates of composite net clinical events and higher rate of mortality).

Thus, the Host-Exam extended study performed post-trial extended follow-up of the patients enrolled in the Host-Exam trial to compare the longer-term outcomes between clopidogrel and aspirin monotherapy.

Study Design

Study included 5,438 patients ≥20 years on DAPT without clinical events for 12 ± 6 months after PCI with drug-eluting stents from March 2014−May 2018 from 37 centers.


  • Patients were randomized to receive,once daily (1:1)
    • Clopidogrel 75 mg or
    • Aspirin 100 mg

Primary Endpoints

  •  Composite of all-cause  death, non-fatal MI,stroke, readmission dueto ACS, and
  •  BARC type ≥3 bleeding

Secondary Endpoints

  • Thrombotic endpoint (cardiac death, non-MI, ischemic stroke, readmission due to ACS, and definite or probable stent thrombosis)
  • Any bleeding endpoint (BARC type> 2 bleeding)

Key Results

Baseline Characteristics
Median follow-up duration (IQR) 5.8 years (4.7−6.2 years)
Age (mean ± SD) 63.3 ± 10.7 years
BMI (mean ± SD) 24.8 ± 3.2 kg/m2
Prevalence of DM 33.8%
Prevalence of CKD 12.4%
Diagnosis of ACS during PCI 71.9%

Significantly higher in aspirin group vs clopidogrel group: 13.5% (367/2,710) vs 8.0% (216/2,648), (P <0.001)

Primary and Secondary Endpoints

Endpoints Assessed Clopidogrel Group (%) (N = 2,431) Aspirin Group (%) (N = 2,286) P-value
Readmission due to ACS 4.6 7.7 <0.001
Major bleeding (BARC type ≥3) 2.6 3.9 0.008
All-cause death 6.2 6.0 0.742

Subgroup* and ITT Analyses

  • Consistent beneficial effect of clopidogrel was observed across all subgroups for primary, secondary thrombotic, and bleeding endpoint.
  • The ITT analyses based on patients randomized in the Host-Exam trial, had similar results to the per protocol analyses for the primary study endpoint (HR = 0.79, P = 0.001). 


  • Antiplatelet regimen was open-labeled and physicians’ discretion on antiplatelet selection could be influenced by multiple factors.
  • The study was not powered to assess the impact of antiplatelet therapy on mortality.
  • Phenotypic and genetic testing for clopidogrel were not performed and generalizability of the study to ethnicities other than East Asian population might be limited. 

For additional details, please refer source publication Kang J, et al.

*Subgroups included age, sex, BMI ≥25 Kg/m2, DM, CKD, multivessel disease, acute MI, ACS, complex PCI, high bleeding risk, proton pump inhibitor usage.


ACS; acute coronary syndrome; BARC, Bleeding Academic Research Consortium; BMI, body mass index; CAD, coronary artery disease; CKD, chronic kidney disease; CV, cardiovascular; DAPT, dual antiplatelet therapy; DM, diabetes mellitus; HOST-EXAM, harmonizing optimal strategy for treatment of coronary artery stenosis-extended antiplatelet monotherapy; HR, hazard ratio; ITT, intention to treat; IQR, interquartile range; MI, myocardial infarction; PCI, percutaneous coronary intervention.


  1. Kang J, Park KW, Lee H, Hwang D, Yang HM, Rha SW, et al. Aspirin vs. clopidogrel for chronic maintenance monotherapy after percutaneous coronary intervention: The Host-Exam extended study. Circulation. 2022. doi: 10.1161/ CIRCULATIONAHA.122.062770. Online ahead of print. PMID: 36342475.