Evidence-based treatments and prescription variability after acute myocardial infarction

Objective: Since there is growing interest in the prescribing of different drugs in various clinical settings, the aim of the study was to verify whet her drug prescribing after acute myocardial infarction can be explained on the basis of evidence-based treatment. Design: All drugs prescribed to 430 patients discharged after acute myocard ial infarction and not referred for revascularisation from three different cardiology departments between 1993 and 1995 were analysed. According to ev idence-based medicine, aspirin, beta-blockers and ACE inhibitors were consi dered effective in reducing mortality; nitrates and calcium antagonists wer e not considered to be effective in reducing mortality. The crude odds rati o (OR) of prescribing for each drug between the three cardiology department s was calculated and then adjusted for confounding clinical variables, test results and concomitant treatments that could affect the rate of prescribi ng. Results: The adjusted OR for clinical variables, test results, and concomit ant treatment showed a similar prescribing pattern for ACE inhibitors (OR 1 .3; 95% confidence interval (CI) from 0.6 to 3.2), aspirin (OR 2.2; 95% CI from 0.8 to 5.5), and beta-blockers (OR 2.2; 95% CI from 0.9 to 5.5). A dif ferent prescribing pattern for nitrates (OR 4.4; 95% CI from 1.6 to 12.3) a nd calcium antagonists (OR 3.4; 95% CI from 1.0 to 12.5) was found. Conclusions: After acute myocardial infarction,evidence-based drug efficacy prescribing pattern among different seems to define a more homogeneous dru g cardiology departments than the prescribing pattern of drugs for which ev idence of efficacy has not been shown.