Background We aimed to analyse initiation of and persistence with P2Y(12) inhibitors after first-time myocardial infarction (MI).

Methods and results Using Danish nationwide registries, we identified patients >= 30years with first-time MI during 1 January 2005-30 June 2016 and subsequent prescriptions of P2Y(12) inhibitors. Independent factors related to initiation of and persistence with P2Y(12) inhibitors were analysed by multivariable logistic regression and a Cox proportional hazards model. Patients were stratified by revascularization strategy: percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG), or medical therapy alone (MTA). Overall, 79597 MI patients were included with 39172 undergoing PCI, 2619 CABG, and 16640 MTA, showing initiation of P2Y(12) inhibitors of 93.4%, 49.0%, and 51.5%, respectively. Congestive heart failure, cerebrovascular disease, cardiac dysrhythmias, renal failure, previous bleeding, and oral anticoagulants were associated with less initiation of P2Y(12) inhibitors. Female sex was associated with less initiation of P2Y(12) inhibitors following MTA. MTA, coronary angiography, cerebrovascular disease, diabetes with complications, previous bleeding, antidiabetics, and ticagrelor as P2Y(12) inhibitor were associated with non-persistence, whereas female sex, advanced age, and concomitant pharmacotherapy with angiotensin-converting enzyme inhibitors, beta-blockers, statins, oral anticoagulants, and aspirin were associated with high persistence.

Conclusion Initiation of P2Y(12) inhibitors in PCI-treated MI patients was high in contrast to those treated with CABG or MTA and patients with certain comorbidities. Further studies on the benefit-risk ratio of P2Y(12) inhibitors in CABG-treated or MTA-treated patients and patients with comorbidities after first-time MI are warranted, as is focus on persistence among patients receiving MTA, patients with comorbidities, and users of ticagrelor.