A team of experts in the U.S. has issued new guidelines for treating high blood pressure. The recommendations are controversial. In the past, hypertension was defined as any blood pressure above 140/90 (the first number measures pressure while the heart is contracting. The second measures pressure between beats, while the heart is momentarily at rest). This is the definition used by physicians in sa国际传媒.
However the team is now advising that high blood pressure should be redefined as anything above 130/80.
If that guideline were accepted, nearly half of all adults in America would be considered hypertensive, as would 80 per cent of those aged 65 and older. The same would apply to Canadians.
We鈥檙e calling this recommendation controversial, in part because of the huge impact it would have, both on the health-care system, and on the daily lives of half the population.
But there are other reasons for caution.
First, if the benefits produced by the guidelines are stated in relative terms, they appear significant. For example, a white male aged 50, in good health, will see his risk of a future heart attack or stroke fall by 14 per cent if his blood pressure is reduced from 140/90 to 130/80. That is the relative improvement.
But if the benefits are stated in absolute terms, the improvement is minute. That same white male will see his risk of a cardiac event within the next 10 years fall from 2.1 per cent to 1.8 per cent.
The absolute risk declines by only three-tenths of one per cent. That鈥檚 not a significant improvement, considering the efforts required to achieve it.
Likewise, a 50-year-old woman in good health also gains a 14 per cent drop in her risk profile. But the absolute change is from 0.7 per cent to 0.6 per cent 鈥� a drop of just one-tenth of one per cent. (Readers who would like to calculate their own risk factors can go to the website ccccalculator.ccctracker.com.)
The same applies to men and women aged 65 who are in good health. The absolute improvement is seven-tenths of a percentage point for women, and just over one percentage point for men.
There are far higher risk levels for individuals with health problems like diabetes, or who are heavy smokers. But the same issue remains. The absolute gains in risk are consistently small.
Second, while there are indeed some benefits from lowering blood pressure with medication, there are also risks. These include potential damage to the kidneys, and the possibility in older individuals of falls caused by dizziness.
In one major U.S. study, which the team relied on heavily, those who benefited from lower blood pressure were actually outnumbered by those who suffered harm.
That is not the end of the story. It might well be argued that a fall resulting in a broken hip is not as life-threatening as a heart attack or stroke. If we have to risk the former to avoid the latter, perhaps that is a gamble worth taking.
Understand that we are not in any way offering advice. In the end, this is a decision each of us must make, in consultation with a physician.
It鈥檚 also fair to say that within the medical community itself, there are widely varying views about the necessity of aiming for blood pressure below 140/90.
However, in the days ahead, it鈥檚 likely the recommendations from this American team will reverberate through sa国际传媒鈥檚 health-care system. The new guidelines have already made waves around the world.
It behooves our own medical experts and administrators to read this study carefully. It is at once more, and less, than it seems.
