Outcome with calcium channel antagonists after myocardial infarction: a community-based study.
OBJECTIVE
We sought to estimate the risk of death and recurrent myocardial infarction associated with the use of calcium antagonists after myocardial infarction in a population-based cohort study.


BACKGROUND
Calcium antagonists are commonly prescribed after myocardial infarction, but their long-term effects are not well established.


METHODS
Patients 25 to 69 years old with a suspected myocardial infarction were identified and followed up through a community-based register of myocardial infarction and cardiac death (part of the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease [MONICA] Project in Newcastle, Australia). Data were collected by review of medical records, in-hospital interview and review of death certificates.


RESULTS
From 1989 to 1993, 3,982 patients with a nonfatal suspected myocardial infarction were enrolled in the study. At hospital discharge, 1,001 patients were treated with beta-adrenergic blocking agents, 923 with calcium antagonists, 711 with both beta-blockers and calcium antagonists and 1,346 with neither drug. Compared with patients given beta-blockers, patients given calcium antagonists were more likely to suffer myocardial infarction or cardiac death (adjusted relative risk [RR] 1.4, 95% confidence interval [CI] 1.0 to 1.9), cardiac death (RR 1.6, 95% CI 1.0 to 2.7) and death from all causes (RR 1.7, 95% CI 1.1 to 2.6). Compared with patients given neither beta-blockers nor calcium antagonists, patients given calcium antagonists were not at increased risk of myocardial infarction or cardiac death (RR 1.0, 95% CI 0.8 to 1.3), cardiac death (RR 0.9, 95% CI 0.6 to 1.2) or death from all causes (RR 1.0, 95% CI 0.7 to 1.3). No excess in risk of myocardial infarction or cardiac death was observed among patients taking verapamil (RR 0.9, 95% CI 0.6 to 1.6), diltiazem (RR 1.1, 95% CI 0.8 to 1.4) or nifedipine (RR 1.3, 95% CI 0.7 to 2.2) compared with patients taking neither calcium antagonists nor beta-blockers.


CONCLUSIONS
These results are consistent with randomized trial data showing benefit from beta-blockers after myocardial infarction and no effect on the risk of recurrent myocardial infarction and death with the use of calcium antagonists. Comparisons between beta-blockers and calcium antagonists favor beta-blockers because of the beneficial effects of beta-blockers and not because of adverse effects of calcium antagonists.
Leitch
J W
JW
Department of Medicine, John Hunter Hospital, Newcastle, New South Wales, Australia. jleitch@ozemail.com.au
McElduff
P
P
Dobson
A
A
Heller
R
R
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D015331:Cohort Studies; D004110:Diltiazem / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D009543:Nifedipine / Q000627:therapeutic use; D014700:Verapamil / Q000627:therapeutic use
D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine