Comparison of Short-term and Standard Duration Dual Antiplatelet Therapy in Elderly Patients: A Pooled Analysis of Five Korean Randomized Clinical Trials

Abstract

Backgrounds and objectives: Data on the optimal duration of dual antiplatelet therapy (DAPT) by age in patients undergoing percutaneous coronary intervention (PCI) are limited. This study assessed clinical outcomes based on age groups and DAPT duration, focusing on patients aged ≥75 years.

Methods: We analyzed data from 10,487 patients across 5 Korean randomized trials examining the impact of DAPT durations on clinical outcomes after drug-eluting stent implantation. Patients were categorized into 2 groups: ≥75 years (n=1,571) and <75 years (n=8,916). Each group was further stratified into short-term DAPT (1-6 months) and standard DAPT (12 months). The primary outcome was major bleeding within 12 months of PCI. Major adverse cardiovascular and cerebrovascular events (MACCE) and net adverse clinical events (NACE), a composite of MACCE and major bleeding, were also compared.

Results: Patients aged ≥75 had a higher risk of major bleeding and MACCE than those aged <75. In patients aged ≥75, standard DAPT was associated with a higher risk of major bleeding than short-term DAPT (hazard ratio [HR], 2.34; 95% confidence interval [CI], 1.17-4.68; p=0.016). In patients aged <75 years, the risk was comparable (HR, 1.45; 95% CI, 1.00-2.10; p=0.053), with no significant interaction between groups (p=0.207). The risks of MACCE and NACE did not differ significantly between DAPT strategies or age groups.

Conclusions: Standard DAPT strategy may increase bleeding risk in elderly patients without reducing ischemic events, despite no significant age-treatment interaction.

Trial registration: ClinicalTrials.gov Identifier: NCT01145079 (RESET), NCT01308281 (IVUS-XPL), NCT01752894 (DETECT-OCT), NCT02494895 (TICO), NCT02513810 (One-Month-DAPT).

Keywords: Clopidogrel; Coronary artery disease; Duration of therapy; Elderly; Platelet aggregation inhibitors; Ticagrelor.