Impact of Nonadherence to Any Antiplatelet Therapy After PCI With Drug-Eluting Stents on Critical Outcomes

BACKGROUND: Lifelong antiplatelet therapy after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) is strongly recommended. However, the extent and temporal variation in the risk of nonadherence to this recommendation remain unclear. OBJECTIVES: The aim of this study was to investigate how nonadherence to any antiplatelet therapy after PCI affects critical cardiac events and whether this effect varies over time. METHODS: This cohort study analyzed Japanese nationwide insurance claims and health checkup records of working-age patients who underwent PCI with DES between April 2016 and March 2022. Nonadherence was defined as prescription coverage of antiplatelet therapy <50% within preceding 90 days. Landmark-time survival analysis with propensity-score matching was conducted every 5 days from 90th to 1,095th days after PCI. The primary outcome was a composite of all-cause death, myocardial infarction, or cardiopulmonary arrest. Results were synthesized to assess temporal variation in the risk magnitude. RESULTS: Among 40,902 patients (mean age, 58.3 ± 8.3 years; 5.5% women 2,240 of 40,902, median IQR follow-up: 653 days Q1-Q3: 235-1,233 days), nonadherence was observed in 1.18% (421 of 35,582) at 90 days and 4.70% (579 of 12,312) at 1,095 days after PCI. Critical cardiac events were more frequent in nonadherent patients (HR: 2.50 95% CI: 1.92-3.26; P < 0.001), with no significant temporal variation across landmark times. CONCLUSIONS: Nonadherence to any antiplatelet therapy after PCI was associated with a more than 2-fold increase in critical cardiac events, irrespective of post-PCI timing throughout 3 years. These findings emphasize the need for sustained efforts by health care providers and patients to maintain drug adherence over a prolonged period.