Early Drug Therapy and In-Hospital Mortality following Acute Myocardial Infarction

Abstract

Background: Early drug therapy in patients with ST-elevation infarction is essential for improved short- and long-term outcomes. Most of the drugs used currently have been extensively studied in the era prior to reperfusion therapies, and thus it is important to assess the value of these drugs in today’s clinical practice and compare the results with those of randomized trials. Objectives: The study assessed the effects of age, gender, risk factors, reperfusion therapy and early drug therapy in patients with acute myocardial infarction with ST elevation or new left bundle-branch block on in-hospital mortality. Methods: The analysis of drug administration and in-hospital mortality is based on the AMIS Plus project, a registry of acute coronary syndromes in Switzerland since 1997. Data from 7,279 patients admitted to participating hospitals between 1997 and 2002 were analyzed, and the effect of factors and drug therapies on in-hospital mortality was assessed by logistic regression analysis. Results: Age and diabetes were identified as factors associated with a higher likelihood of in-hospital mortality, while a significant and important reduction of in-hospital mortality was due to the use of thrombolytic therapy or primary percutaneous coronary intervention (PCI) [relative risk reduction (RRR) of 31%, odds ratio (OR) and 95% confidence interval: 0.69; 0.54–0.87; p = 0.002 for thrombolysis, RRR of 34%; OR 0.66; 0.44–0.99; p = 0.044 for PCI]. Early administration of aspirin or ADP antagonists is associated with a risk reduction of in-hospital mortality by 36% (OR 0.63; 0.45–0.89; p = 0.009) and 50% (OR 0.49; 0.35–0.70; p < 0.001), respectively. The use of unfractionated heparin did not reduce in-hospital mortality. Administration of ACE inhibitors, nitrates or beta-blockers reduced the relative risk of in-hospital death by 40% (OR 0.60; 0.49–0.75; p = 0.009), 42% (OR 0.58; 0.46–0.72; p < 0.001) and 54% (OR 0.46; 0.37–0.57; p < 0.001), respectively. Less frequent use of reperfusion therapies and beta-blockers was documented for older patients. Gender was not a determining factor for in-hospital survival. Conclusion: Early administration of aspirin or ADP inhibition with ticlopidine or clopidogrel as well as the early use of beta-blockers, nitrates and ACE inhibitors had a beneficial effect on in-hospital mortality in the reperfusion era with either thrombolytics or PCI. The association of a beneficial effect of ADP inhibition was more pronounced than that found in randomized trials for non-ST-elevation infarction. However, it cannot be excluded that patients with a lower risk for in-hospital death who were selected for early invasive assessment received more frequently ADP inhibitors and that this influenced this beneficial effect. Diabetes and age had negative effects on in-hospital mortality, and both reperfusion therapy and beta-blockers were much less frequently used in elderly patients.