Potential impact of evidence-based medicine in acute coronary syndromes: Insights from GUSTO-IIb

Objectives. The purpose of this study to determine whether use of cardiac m edications reflects evidence-based recommendations for patients with non-ST elevation acute coronary syndromes. Background. Agency for Health Care Policy and Research practice guidelines for unstable angina recommend the use of cardiac medications based on evide nce from randomized trials. It is unknown whether practitioners in the U.S. , Canada and Europe follow these recommendations in patients with non-ST el evation acute coronary syndromes. Methods. We studied 7,743 patients with non-ST elevation acute coronary syn dromes enrolled in the international Global Use of Strategies to Open Occlu ded Arteries in Acute Coronary Syndromes trial. The use of aspirin, beta-ad renergic blocking agents, angiotensin-converting enzyme inhibitors and calc ium channel blocking agents was determined at discharge for all patients an d "ideal" patients (those with indications and no contraindications). Using published estimates of relative mortality reductions with these drugs, we calculated the lives that could have been saved at 1 year if discharge medi cation use had better matched guideline recommendations. Results. Overall, guideline adherence at discharge in "ideal" patients was 85.6% for aspirin, 59.1% for beta-blockers and 51.7% for angiotensin-conver ting enzyme inhibitors. Calcium channel blockers were given to 26.7% of pat ients with a contraindication to these drugs. These rates were similar acro ss locations of enrollment. Women and older patients less often received as pirin when "ideal," and younger patients more often received calcium channe l blockers when they were contraindicated. If medication use had been more evidence-based, 1-year mortality might have been reduced by a relative 22%. Conclusions. There is significant room for improvement in the use of recomm ended drugs in patients with non-ST elevation acute coronary syndromes. Med ication use that more closely follows recommendations could reduce mortalit y in this population. (J Am Coil Cardiol 1998;32:2023-30) (C) 1998 by the A merican College of Cardiology.