Changes in the use of medications after acute myocardial infarction: possible impact on mortality after myocardial infarction and long-term outcome.

OBJECTIVE

To describe the change in the use of medication after acute myocardial infarction (AMI) and discuss its possible impact on risk and risk indicators for death.

PATIENTS: All patients discharged alive after hospitalization for AMI at Sahlgrenska Hospital (covering half the community of Göteborg, i.e. 250,000 of 500,000 inhabitants) during 1986-1987 (period I) and at Sahlgrenska Hospital and Ostra Hospital (covering the whole community of Göteborg, 500,000 inhabitants) during 1990-1991 (period II).

METHODS

Overall mortality was retrospectively evaluated during 5 years of follow-up.

RESULTS

In all, 740 patients were included in the study during period I and 1448 during period II. The 5-year mortalities were 44.1% for period I patients and 39.3% for period II patients (P = 0.036). The relative risk of death for period II patients was 0.78 [95% confidence interval (CI) 0.67-0.89, P = 0.0005] after adjustment for differences at baseline. There was a significant interaction with a history of congestive heart failure; improvement in duration of survival was found only for patients without such a history. During period I, only 3% of patients were administered fibrinolytic agents, compared with 33% of patients during period II (P < 0.0001). During period I, aspirin was prescribed for 13% of patients discharged from hospital compared with 79% during period II. Other changes in treatment on going from period I to period II included increases in prescription of beta-blockers and angiotensin converting enzyme inhibitors. After adjustment for various risk indicators for death, relative risk of death for those administered fibrinolytic agents was 0.60 (95% CI 0.18-2.02) for patients in the period-I cohort and 0.68% (95% CI 0.51-0.91) for those in the period-II cohort. Adjusted relative risk of death for those prescribed aspirin upon discharge from hospital was 0.81 (95% CI 0.52-1.25) for period-I patients and 0.71 (95% CI 0.56-0.91) for period-II patients. The adjusted relative risk of death for those administered beta-blockers was 0.72 (95% CI 0.55-0.96) for period-I patients and 0.70 (95% CI 0.55-0.90) for period-II patients.

CONCLUSION

Increased use of fibrinolytic agents and aspirin for AMI as well as a moderate increase in use of beta-blockers and angiotensin converting enzyme inhibitors was associated with a parallel reduction in age-adjusted mortality during the 5 years after discharge from hospital. However, this improvement was seen only for patients without histories of congestive heart failure.