Tuesday, September 29, 2015

What is the "Ideal" Systolic Blood Pressure?

Current guidelines for treating high blood pressure are that anyone with systolic blood pressures of 140 mmHg or above (or diastolic pressures above 90mmHg) should be treated to lower their blood pressures below those numbers. But the guidelines beg the question; is there an ideal systolic pressure that is even lower than 140?

According to a recent article in the New York Times, a major new research study shows that lowering systolic pressure to 120 or below reduces the risk of heart attacks, heart failure and strokes by a quarter and reduces the risk of death by a third, compared to just lowering systolic pressure to 140 or below. The findings imply that treatment of high blood pressure should be much more aggressive than the current guidelines suggest.

However, a closer reading of the actual study design reveals an important point: the study examined only patients who are already at risk for heart disease. These were not normal healthy people who just happened to have systolic pressures of 130 mmHg; they were all subjects with systolic blood pressures above 130 mmHg who also had evidence of cardiovascular disease, chronic kidney disease, cardiovascular disease risk factors, or were older than 75.

The results are clear; patients at high risk of cardiovascular disease should be treated more aggressively than in the past, with a goal of lowering their systolic pressures to 120 mmHg or less. But what about normal people who just happen to have a systolic pressure of greater than 120 mmHg? Cardiologists may begin recommending that they be treated, too (to the delight of the companies selling antihypertensive drugs.) But I'm not so sure. All drugs have side effects: when drugs are recommended, the potential benefits should outweigh the risks. And we just don't know whether lowering systolic blood pressure to below 120 in otherwise healthy people is a good idea.

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