The number of adults living with hypertension worldwide has doubled over the last three decades, a new international study has shown.

According to the findings, most of this increase has occurred in low and middle-income countries.

Researchers analysed blood pressure measurements from over 100 million people living in 184 countries over the period 1990-2019. Hypertension was defined as having systolic blood pressure of 140 mm Hg or greater, diastolic blood pressure of 90 mm Hg or greater, or taking medication for high blood pressure.

The study found that during the study period, the number of women with hypertension rose from 331 million to 626 million, while the number of men with hypertension rose from 317 million to 652 million.

Despite the condition being straightforward to diagnose and relatively easy to treat with low-cost drugs, 51% of men with hypertension, and 41% of women, were unaware that they had it in 2019.

Furthermore, 62% of affected men and 53% of affected women were not being treated for the condition in 2019. In fact, blood pressure was controlled using medicines in less than one-fifth of men and one-quarter of women worldwide.

The lowest proportion of people living with hypertension in 2019 was found in Canada and Peru. At the other end of the scale, over half of women in Paraguay had hypertension in 2019, while over half of men were affected in a number of countries including Paraguay, Argentina, Poland, Lithuania and Croatia.

According to the study’s lead author, Prof Majid Ezzati of Imperial College London in the UK, despite medical and pharmacological advances in recent decades, “global progress in hypertension management has been slow, and the vast majority of people with hypertension remain untreated, with large disadvantages in low and middle-income countries”.

However, big improvements in treatment and control rates were seen in some middle-income countries, such as South Africa, Brazil and Turkey.

“Our analysis has revealed good practice in diagnosing and treating hypertension not just in high-income countries, but also in middle-income countries. These successes show that preventing high blood pressure and improving its detection, treatment and control are feasible across low and middle-income settings if international donors and national governments commit to addressing this major cause of disease and death,” Prof Ezzati commented.

He added that policies that enable people in the poorest countries to access healthier foods, improving detection by expanding universal health coverage and primary care, and ensuring uninterrupted access to effective drugs “must be financed and implemented to slow the growing epidemic of high blood pressure in low and middle-income countries”.

This study is published in The Lancet journal.