Mortality rates in elderly patients who take different angiotensin-converting enzyme inhibitors after acute myocardial infarction: a class effect?

BACKGROUND

Several randomized, controlled trials show that angiotensin-converting enzyme (ACE) inhibitors improve survival in patients who have had an acute myocardial infarction. However, existing data from trials do not address whether all ACE inhibitors benefit patients similarly.

OBJECTIVE

To evaluate whether all ACE inhibitors are associated with similar mortality in patients 65 years of age or older who have had an acute myocardial infarction.

DESIGN

Retrospective cohort study that used linked hospital discharge and prescription databases containing information on 18 453 patients 65 years of age or older who were admitted for an acute myocardial infarction between 1 April 1996 and 31 March 2000.

SETTING

109 hospitals in Quebec, Canada.

PATIENTS

7512 patients who filled a prescription for an ACE inhibitor within 30 days of discharge and who continued to receive the same drug for at least 1 year.

MEASUREMENTS

The association between the specific drugs and clinical outcomes was measured by using Cox proportional hazards models, with adjustment for demographic, clinical, physician, and hospital variables and dosage categories, represented by time-dependent variables.

RESULTS

Enalapril, fosinopril, captopril, quinapril, and lisinopril were associated with higher mortality than was ramipril; the adjusted hazard ratios and 95% CIs were 1.47 (95% CI, 1.14 to 1.89), 1.71 (CI, 1.29 to 2.25), 1.56 (CI, 1.13 to 2.15), 1.58 (CI, 1.10 to 2.82), and 1.28 (CI, 0.98 to 1.67), respectively. The adjusted hazard ratio associated with perindopril was 0.98 (CI, 0.60 to 1.60).

LIMITATIONS

The administrative databases did not contain detailed clinical information, and unmeasured factors associated with a patient's risk for death may have influenced physicians' prescription choices.

CONCLUSION

Survival benefits in the first year after acute myocardial infarction in patients 65 years of age or older seem to differ according to the specific ACE inhibitor prescribed. Ramipril was associated with lower mortality than most other ACE inhibitors.