Ask the Doctors

Dear Doctor: I know that high blood pressure increases the risk of heart disease, stroke and more. However, is it still considered a risk factor if it's controlled with medicine?

Dear Reader: High blood pressure is a significant risk factor for heart attacks and strokes because it damages the arteries that supply the heart and the brain, causing them to narrow. Additionally, the heart has to work harder to deal with the resulting elevated blood pressure, increasing the risk of eventual heart failure. There is no disputing these facts.

As for whether someone with high blood pressure controlled by medication has a risk equivalent to somebody without high blood pressure, that's a good question -- and no studies have specifically tried to answer it. But researchers have studied patients with high blood pressure and the attempts to bring the blood pressure to different levels.

A 2015 breakthrough study in the New England Journal of Medicine took 9,361 patients with systolic blood pressure greater than 130 and randomly assigned them to either treatment to keep the blood pressure between 130 and 140 or more aggressive treatment to bring the blood pressure down to 120. The aggressively treated group got their blood pressure down to 121 on average, while the less aggressively treated group had an average systolic blood pressure of 136. The study was stopped after three years because of a 27 percent decrease in the overall death rate in the aggressively treated group.

A 2016 study in The Lancet combined data from 123 studies of hypertension treatment with a total of 613,815 patients. This analysis showed that for every 10-point decrease in blood pressure, the death rate decreased by 13 percent, the stroke rate decreased by 27 percent and the heart failure rate decreased by 28 percent. Like the former study, the benefits were greater with blood pressure below 130.

Lastly, an analysis of 16 studies published in 2016 in the Journal of Hypertension looked at the benefits of more aggressive treatment versus less aggressive treatment of blood pressure. The authors found a 16 percent decrease in death rate with blood pressure below 130 versus blood pressure greater than 130.

Although these studies don't directly answer your question, consider the incremental benefits of lowering your blood pressure. If, on medication, your systolic blood pressure is in the 130s, I would say that you're at greater risk than someone who is not taking medication and who has a blood pressure of 120. If you're on medication and your blood pressure is 120, it's hard to say how that compares to somebody who has a blood pressure of 120 and is not on medication.

The most important lesson is that if you have high blood pressure, you should treat it.

Also, a message for my readers: A recent column on whether to give aspirin for a heart attack in progress referred to two studies in which users received aspirin at various times. In referring to one study, the article stated that earlier users received aspirin an average of 1.6 hours before the onset of symptoms. Obviously, this should have said "after the onset of symptoms."

In referring to the other study, the article stated that patients received aspirin at least 24 hours after the beginning of symptoms. This should have said "up to 24 hours after the beginning of symptoms."

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

More like Ask the Doctors