High Blood Glucose Linked to Poor Outcomes After a Heart Attack

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The association between hyperglycemia on admission and 180-day mortality in acute myocardial infarction patients with and without diabetes, by T. Ainla and colleagues. Diabet Med 22:1321–1324, 2005.

What is the problem and what is known about it so far?

People who suffer heart attacks are often found to have high blood glucose upon admission to the hospital. This is true even if they don't have diabetes. High blood glucose seems to be linked with heart attacks.

Why did the researchers do this particular study?

They wanted to understand the link between diabetes and high blood glucose in people with diabetes when admitted to the hospital. They also wanted to measure the death rate of these people within the first 180 days after a heart attack.

Who was studied?

The study included 779 heart attack patients treated at a teaching hospital in Estonia. They were treated over a two-year period.

How was the study done?

Researchers reviewed medical records to gather information about blood glucose levels and medical treatment for the patients' heart attacks.

What did the researchers find?

Most patients (556 of 779) had no history of diabetes, and had blood glucose levels within a normal range. Some had no history of diabetes and high blood glucose (109 of 779). Of those people with a history of diabetes, some had normal levels of blood glucose (30 of 779) and some had levels higher than normal (84 of 779).

The worst outcomes were seen among people with no history of diabetes but high glucose levels when they were admitted to the hospital. These patients were more likely to have cardiac arrest (no breathing or heartbeat) before reaching the hospital. If they survived, they were nearly 4.5 times more likely to die within 180 days of having a heart attack.

What were the limitations of the study?

The study consisted of a review of medical records. A clinical trial might reach different conclusions. All the information is drawn from one hospital, which might treat heart attacks in subtle ways that could affect the outcome. Health outcomes might be different at another hospital.

Also, the patients' history of diabetes was based on reading medical records. Specific blood tests to diagnose diabetes weren't done for these heart attack patients, so some of them could have had type 2 diabetes without anybody realizing it.

What are the implications of the study?

A high blood glucose level is a signal that a patient is more likely to die of a heart attack. Further research may lead to better ways of treating high blood glucose during these emergencies.