Aim: The present study aimed to investigate temporal trends in myocardial infarction (MI) presentation with or without ST-segment elevation and the association with the use of cardioprotective drugs prior to admission.
Methods and results: Using individual-level linkage of data from Danish nationwide registries, we identified all patients 30 years or older admitted with a first-time MI in the period 2003-2012, and their use of cardioprotective drugs 6 months prior to admission. We calculated incidence rates per 100 000 person-years (IRs) of ST-segment elevation MI (STEMI) and non-STEMI (NSTEMI). We identified 22 247 patients admitted with STEMI and 50 403 with NSTEMI. IRs for NSTEMI decreased by 35% from 194 in 2003 to 126 in 2012, whereas IRs for STEMI peaked in 2007 and subsequently declined from 71 to 65. Preadmission use of cardioprotective drugs increased in both groups from 2003 to 2012. Patients admitted with STEMI had odds ratio (OR) 0.64 [95% confidence interval (CI) 0.61-0.67] for preadmission use of aspirin compared with patients admitted with NSTEMI. Corresponding ORs were 0.82 (CI 0.78-0.87) for statins, 0.87 (CI 0.82-0.91) for beta-blockers, 0.89 (CI 0.85-0.92) for angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and 0.52 (CI 0.44-0.61) for thienopyridines. Also, 30-day and 1-year mortality declined in patients both admitted with STEMI and NSTEMI.
Conclusion: The IRs of MI declined between 2003 and 2012, primarily driven by a 35% reduction in IRs for NSTEMI whereas IRs for STEMI declined after 2007. Preadmission use of cardioprotective drugs increased markedly and was associated with lower ORs of presenting with STEMI than NSTEMI.