Background: The extent and the severity of acute myocardial infarction (MI) is decreasing. Out-of-hospital medical management before the hospital admission could alter clinical presentation in acute MI. We used a large national patient register to investigate the relation between previous medication use (aspirin, beta-blockers, angiotensin-converting enzyme [ACE] inhibitors, and statins) and the risk of presenting with ST-segment elevation MI (STEMI) or non-STEMI.
Methods: We included 103 459 consecutive patients from the Swedish Register of Information and Knowledge About Swedish Heart Intensive Care Admissions (RIKS-HIA) admitted between January 1, 1996, and December 31, 2006, with a first acute MI.
Results: The patients with STEMI (43.5% of the total) were younger, had less prior cardiovascular disease, and used fewer medications before hospitalization. Of the STEMI patients, 61.4% had used no medication vs 45.9% of the patients with non-STEMI. After multiple adjustments, use of aspirin, beta-blockers, ACE inhibitors, and statins before hospitalization were all associated with substantially lower odds of presenting with STEMI. Furthermore, the risk decreased with the number of previous medications, and the use of 3 or more medications was associated with a multiply adjusted odds ratio of presenting with STEMI of 0.48 (99% confidence interval, 0.44-0.52) compared with no medications at admission.
Conclusions: Use of aspirin, beta-blockers, ACE inhibitors, or statins before hospital admission in patients with a first acute MI is associated with substantially less risk of presenting with STEMI. The risk decreases with the increasing number of these medications used before acute MI, underlining the benefit of preventive medication in high-risk patients.