Pharmacological management of acute myocardial infarction in the municipal district of Rio de Janeiro.

Abstract

CONTEXT: International studies have shown a large variation in the utilization patterns of interventions, in acute myocardial infarction. OBJECTIVE: To analyze utilization patterns of pharmacological interventions in acute myocardial infarction and their corresponding effects on hospital mortality. DESIGN: Cross-sectional study. LOCAL: Hospitals of the Brazilian National Health System (SUS) in the municipal district of Rio de Janeiro. SAMPLE: A stratified hospital sample of 391 medical records selected from the 1,936 admissions registered in the SUS Hospital Information System (SIH/SUS) with a main diagnosis of acute myocardial infarction, in the studied district in 1997. MAIN MEASUREMENTS: Sex, age, time to treatment, risk factors, severity factors, diagnosis confirmation, use of pharmacological interventions, hospital death, contraindication of the use of thrombolytic therapy, contraindication of aspirin use. RESULTS: We reviewed 98.2% of the sampled medical records. Acute myocardial infarction diagnosis was confirmed in 91.7% (95% CI 88.3 to 94.2). 61.5% were men and 38.5% women, with an average age of 60.2 years (SD 2.4). The median time interval between symptom onset and hospital admission was 11 hours. Hospital mortality was 20.6% (95% CI 16.7 to 25.0). Intravenous thrombolytic therapy was used in 19.5% (95% CI 15.8 to 23.9) of the cases; aspirin in 86.5% (95% CI 82.5 to 89.6); beta-blockers in 49.0% (95% CI 43.8 to 54.1); angiotensin-converting enzyme (ACE) inhibitors in 63.3% (95% CI 58.2 to 68.1); nitrates in 82.0% (95% CI 82.4 to 89.6); heparin in 81.3% (95% CI 76.9 to 85.0); calcium antagonists in 30.5% (95% CI 26.0 to 35.4). There was a significant variation in the use of thrombolytic therapy, beta-blockers, ACE inhibitors, calcium antagonists and heparin among hospitals of different juridical nature. CONCLUSIONS: There was underutilization of some interventions with well-established efficacy (thrombolytic therapy, aspirin, beta-blockers and intravenous nitrates). The use of calcium antagonists, not supported by scientific evidence in acute myocardial infarction, was quite frequent. A logistic model documented the benefit of aspirin, beta-blockers and ACE inhibitor use in reducing the chance of hospital death.