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18-11-2016 | Hypertension | News | Article

Substantial burden of high blood pressure in low- and middle-income countries

medwireNews: The number of people living with high blood pressure (BP) has almost doubled worldwide over the past 4 decades, with the biggest rise in low- and middle-income countries, according to an analysis of data from 19.1 million people.

“Raised blood pressure has transitioned from a risk factor largely affecting high-income countries to one that is now most prevalent in low-income countries in south Asia and sub-Saharan Africa, while being a persistent health issue in central and eastern Europe,” write the researchers in The Lancet.

Majid Ezzati (Imperial College London, UK) and colleagues from the non-communicable disease (NCD) Risk Factor Collaboration estimated that the total number of adults living with high BP across the globe increased from 594 million in 1975 to 1.13 billion in 2015.

They found that the biggest rise in the proportion of adults with high BP occurred in low- and middle-income countries in sub-Saharan Africa and South Asia. In high-income western and Asia Pacific countries, however, the number of adults with high BP decreased steadily since 1975.

Ezzati and colleagues pooled data from 1479 studies that measured BP in adults. Because no or few data sources were available for some countries, particularly those in sub-Saharan Africa and the Caribbean, they produced estimates for these countries using a statistical model.

They note that: “The absence or scarcity of data is reflected in wider uncertainty intervals of our estimates for these countries and regions, emphasising the importance of NCD-oriented surveillance.”

Overall, age-standardized mean systolic BP remained similar over the study period in men, increasing by 0.07 mmHg per decade (126.6 mmHg in 1975 and 127.0 mmHg in 2015), and decreased by 0.47 mmHg per decade in women (123.9 mmHg in 1975 and 122.3 mmHg in 2015). The authors observed similar trends for diastolic BP.

The largest decrease in mean systolic BP over the study period was seen in high-income Asia Pacific, with a drop of 2.4 mmHg per decade for men and 3.2 mmHg per decade for women. The researchers’ estimates suggested that mean BP also decreased in women living in central and eastern Europe, Latin America and the Caribbean, central Asia, Middle East, and north Africa, but “little or no change” in mean systolic or diastolic BP occurred in men in these regions.

Mean systolic and diastolic BP “might have increased” in both men and women in east and southeast Asia, south Asia, Oceania, and sub-Saharan Africa, the team reports.

In light of these findings, the researchers say that “[t]he global target of reducing raised blood pressure prevalence by 25% by 2025 is unlikely to be achieved” in low-income settings.

The author of an accompanying commentary, Kazem Rahimi (University of Oxford, UK) agrees, noting that “if no additional measures are taken,” substantial reductions in BP in such settings are unlikely.

However, he believes that “substantial and continuous reductions in mean blood pressure and prevalence of raised blood pressure are achievable,” as demonstrated by steadily decreasing trends in high-income countries.

“Effective control of raised blood pressure requires collaborative, multisectoral, national efforts to improve implementation of available evidence,” Rahimi recommends.

He concludes that: “The failure to tackle this issue more decisively will come at a high cost, particularly to disadvantaged individuals and societies.”

By Claire Barnard

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016