Use of evidence-based therapy at discharge for patients with acute myocardial infarction: Retrospective audit of medical records

Abstract

Background: Various guidelines are available outlining optimal therapy for patients with acute myocardial infarction. Canadian institutions providing care for such patients have been encouraged to evaluate their care processes using specific indicators. Objective: To determine the proportion of patients with acute myocardial infarction discharged from a single health authority for whom acetylsalicylic acid (ASA), adrenergic β-receptor antagonists (β-blockers), angiotensin-converting enzyme (ACE) inhibitors, or 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) had been prescribed. Methods: Patients treated over a 12-month period (April 1, 2004, to March 31, 2005) for whom the most responsible diagnosis was acute myocardial infarction were eligible for inclusion in this review. Retrieved data included diagnosis, demographic information, comorbidities, and medications at the time of admission and discharge. Rates of discharge prescribing for the 4 drug classes were calculated for all patients and for "ideal" patients (those without documented contraindications). Rates were compared with published benchmark values. Results: Medical records for a total of 346 eligible patients were reviewed. Mean age was 65.3 years (standard deviation 13.4 years), and 226 (65.3%) of the patients were male. The coded diagnosis was ST-elevation myocardial infarction for 91 patients (26.3%), non-ST-elevation myocardial infarction for 164 (47.4%), and myocardial infarction not specified for 91 (26.3%). For "ideal" patients, the prescribing rates were 99.0% (308 of 311 patients) for ASA, 96.3% (310 of 322 patients) for β-blockers, 90.4% (264 of 292 patients) for ACE inhibitors, and 88.8% (278 of 313 patients) for statins. Conclusions: Rates of prescribing of ASA, β-blockers, ACE inhibitors, and statins for "ideal" patients discharged after treatment for acute myocardial infarction exceeded the published Canadian benchmark rates (&γε; 90% for ASA, &γε; 85% for β-blockers and ACE inhibitors, ≥ 70% for statins).