USE OF BETA-BLOCKING-AGENTS IN SECONDARY PREVENTION AFTER MYOCARDIAL-INFARCTION - A CASE FOR EVIDENCE-BASED MEDICINE - GISSI EXPERIENCE, 1984-1993

Aims Many clinical trials conducted in the 1970s and early 1980s have shown that the long-term use of beta-blockers after an acute myocardia l infarction significantly reduces mortality and reinfarction rates. T his study assessed the impact of these findings in clinical practice. Methods We retrospectively analysed the beta-blocker prescriptions for 36 817 patients with acute myocardial infarction included in three la rge randomized clinical trials (Gruppo Italiano di Studio sulla Soprav vivenza nell'Infarto Miocardico - GISSI, 1, 2 and 3), conducted by a h ighly representative sample (about 75%) of Italian coronary care units in 1984-85, 1988-89 and 1991-93. Results The prescription of beta-blo ckers at discharge increased gradually from 8.5% in 1988-85 to 25.0% i n 1988-89 and to 31.4% in 1991-93. A similar trend was apparent for be ta-blocker prescriptions 6 months after acute myocardial infarction. T he strongest predictors of beta-blocker prescription are the presence of post-infarctual angina and a history of arterial hypertension. Besi des the classical contraindications, advanced age, transitory cardiac failure or arrhythmias in the acute phase of acute myocardial infarcti on are important predictors of nonprescription. Conclusion The use of beta-blockers after acute myocardial infarction in Italy has increased more than three-fold in the last decade, but they are still prescribe d to too few patients, especially those at higher risk, for whom the e xpected benefit is greater.