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Am Fam Physician. 2022;105(2):203-204

Clinical Question

In people needing chronic antiplatelet therapy after completing dual antiplatelet therapy following percutaneous coronary interventions (PCIs) with drug-eluting stents, is clopidogrel (Plavix) monotherapy safer and more effective than aspirin monotherapy in preventing future coronary events?

Bottom Line

In this study, clopidogrel monotherapy caused fewer subsequent events compared with aspirin monotherapy in stable patients who completed dual antiplatelet therapy after PCI with drug-eluting stents. (Level of Evidence = 2b)


This open-label study took place in 37 sites in South Korea. Adults who had completed six to 18 months of dual anti-platelet therapy after PCI with drug-eluting stents were randomized to receive clopidogrel, 75 mg daily (n = 2,719), or aspirin, 100 mg daily (n = 2,278), for two years. The included patients had no events during the period of dual antiplatelet therapy. The research team evaluated the participants 12 months and 24 months after randomization. They used intention-to-treat analysis for the main outcome (a composite of all-cause mortality, nonfatal myocardial infarction, stroke, hospitalization for acute coronary syndrome, and major bleeding complications). The authors had several other planned analyses, but did not include statistical adjustments to guard against type 1 errors (i.e., finding differences by chance). The primary outcome occurred in 5.6% of clopidogrel-treated patients and 7.6% of aspirin-treated patients (number needed to treat [NNT] = 51; 95% CI, 31 to 152). Compared with those taking aspirin, patients taking clopidogrel had fewer strokes (NNT = 110; 95% CI, 67 to 282), fewer hospitalizations (NNT = 65; 95% CI, 40 to 161), and less major bleeding (NNT = 138; 95% CI, 71 to 1,703). There were no significant differences in all-cause mortality or nonfatal myocardial infarction. A statistical adjustment for multiple analyses indicates that it is possible there was no difference in the rate of major bleeding.

Study design: Randomized controlled trial (nonblinded)

Funding source: Industry and government

Allocation: Concealed

Setting: Outpatient (specialty)

Reference: Koo B, Kang J, Park KW, et al. HOST-EXAM investigatorsAspirin versus clopidogrel for chronic maintenance monotherapy after percutaneous coronary intervention (HOST-EXAM): an investigator-initiated, prospective, randomised, open-label, multicentre trial. Lancet. 2021;397(10293):2487–2496.

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