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Evidence Summary

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Blood pressure–lowering drugs reduce strokes and deaths in people with mild high blood pressure and no cardiovascular disease

Sundstrom J, Arima H, Jackson R, et al. Effects of Blood Pressure Reduction in Mild Hypertension: A Systematic Review and Meta-analysis. Ann Intern Med. 2015;162:184-91.

Review question

In people who have mild high blood pressure (BP), but not cardiovascular (CV) disease, do drugs used to lower BP reduce CV events (e.g., stroke, heart attack, coronary heart disease)?

Background

High BP is usually defined as having a systolic BP of 140 mm Hg or more or a diastolic BP of 90 mm Hg or more. Mild high BP is defined as having a systolic BP of 140 to 159 mm Hg or a diastolic BP of 90 to 99 mm Hg. High BP often doesn’t cause symptoms but, over time, can cause strokes or heart problems, including heart attacks.

Drugs used to lower high BP can reduce risk of CV events, although they may work differently in people with mild high BP.

How the review was done

The researchers included data from randomized controlled trials published up to June 2014. The trials included 15,266 people with mild high BP.

The key features of the trials were:

  • people were 18 years of age or older and initially did not have CV disease (e.g., previous stroke, angina, heart attack, heart surgery or other heart procedures, kidney failure [where kidneys can no longer get rid of waste and fluid from the blood], or peripheral artery disease [blockages or narrowing in the blood vessels in the legs and arms]);
  • drugs were given to lower BP;
  • most drugs were compared with placebo, although some trials compared more-intensive with less-intensive drug regimens; and
  • people were treated for 4 to 5 years.

What the researchers found

Compared with control (placebo or less-intensive drug regimens), drugs used to lower BP:

  • reduced strokes and deaths; and
  • had similar rates of coronary events (heart attack or death caused by coronary heart disease) or heart failure (problems with the heart’s ability to pump blood).

Conclusion

Blood pressure–lowering drugs reduce strokes and deaths in people who have mild high blood pressure and no cardiovascular disease.

Blood pressure (BP)-lowering drugs vs control* in people with mild high BP and no cardiovascular (CV) disease

Outcomes

Number of trials and people

Rate of events with BP-lowering drugs over about 5 years

Rate of events with control over about 5 years

Absolute effect of BP-lowering drugs over about 5 years

Major CV events†

9 trials (12,970 people)

4.8%

5.5%

No effect‡

Stroke

9 trials (12,411 people)

1.5%

2.1%

About 6 fewer people out of 1000 had a stroke

Heart attack

8 trials (12,925 people)

2.6%

2.8%

No effect‡

Heart failure

6 trials (5,629 people)

2.3%

2.8%

No effect‡

Death caused by CV events

6 trials (5,881 people)

3.3%

4.4%

About 11 fewer people out of 1000 died because of a CV event

Death by any cause

10 trials (15,239 people)

3.8%

4.8%

About 10 fewer people out of 1000 died

*Most trials compared BP-lowering drugs with placebo; some compared more-intensive with less-intensive drug regimens.

†Major CV events include any of stroke, coronary heart disease (heart attack), heart failure (problems with the heart’s ability to pump blood), or death caused by CV events.

‡Although the rates for the 2 groups look a little different, the differences were not statistically significant. This means that the differences could simply be due to chance rather than due to the different treatments.




Glossary

Angina
Chest pain due to reduced blood flow to the heart.
Coronary events
Adverse events caused by conditions affecting the coronary arteries that supply oxygen and blood to the heart.
Coronary heart disease
Also known as coronary artery disease (CAD), is a narrowing of the blood vessels (coronary arteries) that supply oxygen and blood to the heart.
Diastolic
The lower number in a blood pressure reading. It is the pressure when the heart rests between beats.
Placebo
A harmless, inactive, and simulated treatment.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systolic
The higher number in a blood pressure reading. It is the pressure in the arteries when the heart beats.
Vascular
The body's network of blood vessels. It includes the arteries, veins, and capillaries that carry blood to and from the heart.

Related Web Resources

  • Blood pressure screening

    Health Link B.C.
    The Canadian Hypertension Education Program recommends that all adults get their blood pressure tested when they visit the doctor. If you are at risk for heart disease or a disease caused by high blood pressure, you should get your blood pressure checked more often.
  • The evidence on salt? The jury is still out

    Evidence-based Living
    Eating too much salt can make existing high blood pressure and heart disease worse. More unbiased and high quality research is needed to know whether salt intake is really a risk for healthy adults.
  • Salt and sodium: Heart risks and disease

    Harvard School of Public Health
    Eating too much salt can increase your blood pressure and lead to heart disease, especially if you are over 50, have high blood pressure or diabetes, or are African American. Try to eat less than a teaspoon of salt a day.
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