The Effect of Diabetes and High Blood Pressure on Stroke

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The impact of history of hypertension and type 2 diabetes at baseline on the incidence of stroke and stroke mortality, by G. Hu and colleages. Stroke 36:2538–2543, 2005.

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

High blood pressure and type 2 diabetes often go hand-in-hand. At least 40% percent of people with diabetes have high blood pressure, which often leads to stroke. High blood pressure may make stroke more likely in people with diabetes.

What isn't clear is how much high blood pressure, diabetes, or both have to do with one's chances of having a stroke.

Why did the researchers do this particular study?

Researchers wanted to measure how diabetes and high blood pressure affects one's chances of having a stroke, particularly if the person has both conditions. They also wanted to see whether strokes are more likely to be deadly in people with diabetes.

Who was studied?

The study included 49,582 people in Finland who were between 25 and 74 years old. None of the participants had a history of stroke or coronary heart disease (disease of the heart's blood vessels).

How was the study done?

Researchers performed detailed surveys over several years. Study participants initially completed a questionnaire that asked in-depth information about their health. High blood pressure and diabetes status was determined by asking about the type of medical care they received and the medications they took.

Participants were checked on for about 19 years. Information about stroke and stroke-related deaths were gathered from national information sources and computerized databases.

What did the researchers find?

Both high blood pressure and diabetes raise the chance of a person having a stroke, but the effect of having both was dramatic. A person with high blood pressure and diabetes is 4.5 times more likely to have a stroke, and if they do have a stroke, they are more than 9 times more likely to die from it than somebody with neither disease.

What were the limitations of the study?

The blood pressure and diabetes status of each participant was determined by whether or not they were prescribed drugs to treat the conditions. This information may not be complete or accurate since it was self-reported by the participants. Some cases of high blood pressure and diabetes may have been missed. Also, researchers had no way of knowing whether people took their medications as prescribed.

What are the implications of the study?

Controlling high blood pressure is important for any person, but doctors should pay particular attention to people with type 2 diabetes.

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