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 percent of the sampled medical records. Acute myocardial infarction diagnosis was confirmed in 91.7 percent (95 percent CI 88.3 to 94.2). 61.5 percent were men and 38.5 percent 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 percent (95 percent CI 16.7 to 25.0). Intravenous thrombolytic therapy was used in 19.5 percent (95 percent CI 15.8 to 23.9) of the cases; aspirin in 86.5 percent (95 percent CI 82.5 to 89.6); beta-blockers in 49.0 percent (95 percent CI 43.8 to 54.1); angiotensin-converting enzyme (ACE) inhibitors in 63.3 percent (95 percent CI 58.2 to 68.1); nitrates in 82.0 percent (95 percent CI 82.4 to 89.6); heparin in 81.3 percent (95 percent CI 76.9 to 85.0); calcium antagonists in 30.5 percent (95 percent 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