Efficacy of long-term anticoagulant treatment in subgroups of patients after myocardial infarction

Effect of drug combinations on admission for recurrent myocardial infarction

OBJECTIVE

To determine the effect of the number of different drugs with adherence to medication of at least 70% on recurrent admission for myocardial infarction (MI) in patients with a history of MI.

DESIGN

Nested case-control study in a dynamic cohort.

SETTING

PHARMO database that contains pharmacy dispensing records and hospital discharge records of 350,000 Dutch citizens.

SUBJECTS

All patients admitted to hospital for first MI (ICD-9 410) from 1991 to 2000 with at least a 30-day survival after admission. Cases were admitted for recurrent MI and were matched for age, sex, and year of admission with controls who did not have a recurrent MI.

MAIN OUTCOME MEASURE(S)

Odds ratio with 95% CI for admission for recurrent MI. Exposure was the number of preventive drugs (antiplatelet agents, statins and beta blockers or ACE inhibitors) used for at least 70% of the time.

RESULTS

389 cases were matched with 2344 controls. The use of one drug was associated with a 6% odds reduction (95% CI 30% reduction to 28% increase) for admission for recurrent MI. The use of two or three drugs was associated with reductions of 26% and 41% (47% reduction to 3% increase and 6% to 63% reduction, respectively). Addition of one drug caused a 16% reduction (4% to 26%).

CONCLUSIONS

Multiple drug treatment decreases admissions for recurrent MI in patients with a history of MI. Every addition of a drug, regardless of drug class, reduces the risk even further. These results support the treatment strategies as applied in daily practice.

Drug Therapy for Prevention of Recurrent Myocardial Infarction

OBJECTIVE

To provide an evidence-based overview of drug treatment for long-term secondary prevention of myocardial infarction (MI).

DATA SOURCES

We conducted searches of MEDLINE (1966-August 2002), the Cochrane Controlled Trial Register, and the reference list of each identified study.

STUDY SELECTION/DATA EXTRACTION

Trials and meta-analyses were included using the following criteria: (1) randomized trials, (2) description of identification procedure, inclusion criteria, outcome measures, and statistical methods, (3) confirmed MIs, (4) treatment continued for at least 1 month, and (5) all-cause mortality as primary outcome; other events as secondary outcomes. All authors interpreted the results from trials that met the inclusion criteria.

DATA SYNTHESIS

In randomized clinical trials, low-dose aspirin, high-intensity oral anticoagulants, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and statins decreased the risk of mortality and reinfarction after MI. Randomized clinical trials using calcium-channel blockers, antiarrhythmics, and hormone replacement therapy did not show benefits in patients with prior MI. Effects of the combined use of aspirin or oral anticoagulants with beta-blockers or ACE inhibitors plus statins must be derived from subgroup analysis of trials, but seem to be beneficial.

CONCLUSIONS

The use of at least aspirin or an oral anticoagulant, a beta-blocker or an ACE inhibitor, plus a statin should be incorporated in the treatment routine. Clopidogrel treatment might be an alternative to aspirin. Standard addition of a beta-blocker to ACE inhibitor-treated patients without reduced left-ventricular ejection fraction seems to be untimely.