High blood pressure: Calculating your risk

(This article was first printed in the April, 2004 issue of the Harvard Men's Health Watch. For more information or to order, please go to http://health.harvard.edu/men.)

Doctors learned how to measure blood pressure in 1896 - and it didn't take them long to learn that high blood pressure is a major health hazard. Hypertension plays an important role in causing heart attacks and strokes, the first and third leading causes of death in America. Without treatment, it also contributes to congestive heart failure, kidney failure, memory loss and dementia, and visual impairment. And because high blood pressure can damage arteries anywhere in the body, it can also lead to erectile dysfunction, particularly in older men.

There is no doubt that hypertension is harmful, nor is there any doubt that treatment is very helpful. Every man should know his blood pressure and understand what the numbers mean; virtually every man should also do whatever it takes to bring his pressure down below 140/90 by following a healthful lifestyle and, if necessary, taking medication (see Harvard Men's Health Watch, January 2004). But some people seem to think they can beat the odds, and that the statistics and guidelines apply only to the other guy. Whether or not you are tempted to play roulette with your cardiovascular health - and your life - you may find it useful to see exactly what high blood pressure may mean for you, and one study allows you to calculate your personal risk.

To develop the scoring system, scientists in England, France, and Belgium analyzed eight different studies from Europe and North America; collectively, the data included 47,088 men and women who were observed for an average of more than five years.

You'll need to know your height and the major events in your medical history to use the chart. You'll also need some information from your doctor, including your total cholesterol, your kidney function as measured by your blood creatinine level, and whether your electrocardiogram shows an enlargement of your heart's main pumping chamber (left ventricular hypertrophy). And, of course, you'll need to know your blood pressure - but you'll need only your higher, or systolic, number, which is the pressure in your arteries when your heart is pumping blood out to the rest of your body. That's because doctors have turned traditional "wisdom" upside down now that they've learned that the systolic pressure is actually more important than the diastolic pressure, which is the lower number, measured while the heart is relaxing and refilling between beats.

Once you have this information, use Table 1 to determine your blood pressure risk score. Table 2 will help you translate that score into the percentage risk for dying from a hypertension-related cardiovascular problem over the next five years.

Knowing your risk is one thing, doing something to reduce it is another. But the scientists also found that antihypertensive therapy can do just that, lowering the risk of heart attack by more than 15% and of stroke by more than 36%.

The risk tables should convince you that high blood pressure is an important health hazard and that treatment will reduce its risk. But it contains other important lessons as well. The study shows that men are at greater risk than women; just being male adds 12 points to the risk score. In addition, age is important; the older you are, the greater your risk, which is why doctors now believe in treating elevated pressure at any and every age. Oddly enough, shorter men appear to be at higher risk than taller men.

Above all, perhaps, the scoring system reminds us that for all its importance, blood pressure is just one of several crucial cardiovascular risk factors. For optimal protection, lower your cholesterol and blood sugar as well as your blood pressure. Don't smoke. Start with diet, exercise, and weight control, then work with your doctor to add medications that may be helpful. If you succeed, the blood pressure point score can point your way to better health.