Potential impact of evidence-based medicine in acute coronary syndromes: insights from GUSTO-IIb. Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes trial.

OBJECTIVES The purpose of this study to determine whether use of cardiac medications 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 evidence from randomized trials. It is unknown whether practitioners in the U.S., Canada and Europe follow these recommendations in patients with non-ST elevation acute coronary syndromes. METHODS We studied 7,743 patients with non-ST elevation acute coronary syndromes enrolled in the international Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes trial. The use of aspirin, beta-adrenergic blocking agents, angiotensin-converting enzyme inhibitors and calcium channel blocking agents was determined at discharge for all patients and "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 medication 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-converting enzyme inhibitors. Calcium channel blockers were given to 26.7% of patients with a contraindication to these drugs. These rates were similar across locations of enrollment. Women and older patients less often received aspirin when "ideal," and younger patients more often received calcium channel 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 recommended drugs in patients with non-ST elevation acute coronary syndromes. Medication use that more closely follows recommendations could reduce mortality in this population.