Why do we need systematic reviews A patient with myocardial infarction in 1981

A likely scenario in the early 1980s, when discussing the discharge of a patient who had suffered an uncomplicated myocardial infarction, is as follows: a keen junior doctor asks whether the patient should receive a beta-blocker for secondary prevention of a future cardiac event. After a moment of silence the consultant states that this was a question which should be discussed in detail at the Journal Club on Thursday. The junior doctor (who now regrets that she asked the question) is told to assemble and present the relevant literature. It is late in the evening when she makes her way to the library. The MEDLINE search identifies four clinical trials.23-26 When reviewing the conclusions from these trials (Table 1.1) the doctor finds them to be rather confusing and contradictory. Her consultant points out that the sheer amount of research published makes it impossible to keep track of and critically appraise individual studies. He recommends a good review article. Back in the library the junior doctor finds an article which the BMJ published in 1981 in a "Regular Reviews" section.27 This narrative review concluded:

Thus, despite claims that they reduce arrhythmias, cardiac work, and infarct size, we still have no clear evidence that beta-blockers improve long-term survival after infarction despite almost 20 years of clinical trials.21

Table 1.1 Conclusions from four randomised controlled trials of beta-blockers in secondary prevention after myocardial infarction.

The mortality and hospital readmission rates were not significantly different in the two groups. This also applied to the incidence of cardiac failure, exertional dyspnoea, and frequency of ventricular ectopic beats.

Reynolds and Whitlock23

Until the results of further trials are reported long-term beta-adrenoceptor blockade (possibly up to two years) is recommended after uncomplicated anterior myocardial infarction.

Multicentre International Study24

The trial was designed to detect a 50% reduction in mortality and this was not shown. The nonfatal reinfarction rate was similar in both groups.

Baber et al.25

We conclude that long-term treatment with timolol in patients surviving acute myocardial infarction reduces mortality and the rate of reinfarction.

The Norwegian Multicentre Study Group26

The junior doctor is relieved. She presents the findings of the review article, the Journal Club is a full success and the patient is discharged without a beta-blocker.

Your Heart and Nutrition

Your Heart and Nutrition

Prevention is better than a cure. Learn how to cherish your heart by taking the necessary means to keep it pumping healthily and steadily through your life.

Get My Free Ebook

Post a comment