High blood pressure, or hypertension, is a chronic condition that affects millions of Australians.

It usually doesn’t produce symptoms, so you may not know you have it until a visit to the doctor. But if left untreated, hypertension can increase your risk of a number of nasty conditions – like stroke, heart attack and kidney disease.

In 2017 the US changed their definition of hypertension – lowering the threshold for what’s considered high blood pressure from 140/90 to 130/80. The thinking was that they could catch more people in the early stages of hypertension and treat them, leading to reduced numbers of people experiencing strokes and heart attacks.

But it also meant that almost half the US population would now be considered to have high blood pressure, with all the associated costs of treatment and doctor visits that comes with. Overall, is it a beneficial change?

Researchers in Germany wanted to answer that question, and to do that they looked at a group of more than 11,000 people over 10 years.

These were ordinary German people between the ages of 24 and 70. This age range was important, because a previous study looking at the same question (which prompted the change in US guidelines) only looked at older people who already had an increased risk of heart disease.

The researchers separated them into different groups – one group were those who would be considered to have hypertension under the old US definition (140/90), another who were or became hypertensive under the new definition (130/80) and then a generally healthy portion of the population. They counted the number of cardiac events in each group over the 10 year period.

What they found was that in the first group – the 140/90 group – the rate of death by cardiovascular-related causes (like heart attack and stroke) did go up by about 50 per cent, as expected. But in the second group, the 130/80 group, there wasn’t a significant increase in death by cardiovascular causes.

In fact, the overall rates of death were similar to those with lower blood pressure. What’s more, those who were diagnosed as hypertensive were more likely to be depressed, which the researchers say could be an effect of being labelled with an unhealthy diagnosis and the stress this can cause people.

Implications

It seems there’s no benefit to lowering the threshold for high blood pressure in people who aren’t at high risk (meaning a previous heart attack, stroke or diabetes), and it may even do some psychological harm through a labelling effect. In Australia, we follow the 140/90 reading to define the threshold for high blood pressure.

But that doesn’t mean you can rest on your laurels if you’re below that number. Blood pressure often creeps up as we age, but steps you can take to limit any increase include exercise, reducing salt and alcohol intake and lowering your weight.

Last Reviewed: 06/02/2020

© Norman Swan Medical Communications.



References

For reference: Atasoy, et al. (2018). Association of hypertension cut-off values with 10-year cardiovascular mortality and clinical consequences: a real-world perspective from the prospective MONICA/KORA study. European Heart Journal doi: 10.1093/eurheartj/ehy694.