Global Rates of High Systolic BP, Related Disability Climb

Marlene Busko

January 10, 2017

SEATTLE, WA — In the past 25 years, the number of people with elevated systolic blood pressure (SBP) has greatly increased, as have deaths and lost disability-adjusted life-years (DALYs) related to elevated SBP[1].

These findings, from a study by Dr Mohammad H Forouzanfar (University of Washington, Seattle) and colleagues based on data from the Global Burden of Disease, Injuries, and Risk Factor Study 2015 (GBD 2015), were published in the January 10, 2017 issue of the Journal of the American Medical Association.

The researchers looked at two measures of SBP: >110 to 115 mm Hg, "the level where in high-quality prospective cohort studies we begin to see increased risk of death" and >140 mm Hg, "the level at which physicians have historically been providing people with blood-pressure–lowering medications and [where] the diagnostic category of hypertension occurs," study coauthor Dr Gregory A Roth (University of Washington, Seattle) explained to heartwire from Medscape.

"The most important finding . . . is that elevated SBP is a major source of lost health all over the world," he said. Health lost because of elevated blood pressure "varies dramatically depending on where you live," he continued. "For example, in Eastern Europe up to almost 20% of all health loss can be ascribed to high blood pressure. . . . [Yet] it's a highly treatable condition, and unfortunately it's going untreated in many parts of the world."

"These data cannot inform clinical practice guidelines regarding appropriate levels for initiation of blood-pressure–lowering therapy or goal levels for treatment," Drs Mark D Huffman and Donald M Lloyd-Jones (Northwestern University Feinberg School of Medicine, Chicago, IL) caution, in an accompanying editorial[2].

"However, these data strengthen the case to lower the risk for cardiovascular diseases in those with SBP of 140 mm Hg or higher by all effective means available, including improving uptake of healthy diets, minimizing weight gain or promoting weight loss in overweight and obese individuals, and promoting uptake and adherence to effective blood-pressure–lowering drugs as well as management of related cardiovascular risk."

Estimating Global Hypertension Burden

Forouzanfar and colleagues analyzed data from 8.69 million participants in studies from 154 countries and used models for 41 other countries to estimate country-level rates of elevated SBP and lost DALYs and deaths from heart disease, stroke, atrial fibrillation, cardiomyopathy, aortic aneurysm, peripheral vascular disease, rheumatic heart disease, endocarditis, chronic kidney disease, and other cardiovascular diseases related to elevated SBP.

They estimated that from 1990 to 2015, the number of individuals with SBP of at least 110 to 115 mm Hg rose by 11% (from 1.87 billion to 3.47 billion) and those with SBP of 140 mm Hg or higher rose by 18% (from 0.6 billion to 0.9 billion).

Meanwhile, the number of deaths related to SBP of at least 110 to 115 mm Hg rose by 49% (from 7.2 million to 10.7 million), and those related to SBP of 140 mm Hg or higher rose by 51% (from 5.2 million to 7.8 million).

During this time, lost DALYs associated with SBP of at least 110 to 115 mm Hg increased from 147 million to 212 million, and those associated with SBP of 140 mm Hg or greater increased from 96 million to 143 million.

More than half of the lost DALYs associated with SBP of at least 110 to 115 mm Hg lived in five countries—China, India, Russia, Indonesia, and the US—which was "driven in large part by the [large] population in these countries," Roth explained.

This study provides "slightly different yet overlapping estimates" of the global burden of hypertension compared with studies such as a recent one from the NCD Risk Factor Collaboration, Huffman and Lloyd Jones note. That study reported that, worldwide, hypertension nearly doubled since 1975 to over 1.1 billion in 2015.

Nevertheless, even though the extensive amount of data from the GDB project "are fuzzy and imperfect, they provide valuable estimates of current global disease burden," Huffman and Lloyd Jones write. The study reinforces that "preventing the onset of clinical hypertension (ie, primary prevention) and blunting or abolishing the rise in SBP from 110 mm Hg through prehypertensive levels to 140 mm Hg or higher is imperative to prevent premature death and disability from cardiovascular diseases.

"At the other end of the prevention spectrum, natural experiments and policy-driven programs suggest that sodium reduction in the food supply, particularly in high-income countries, appears useful, [but] translating these lessons to low- and middle-income countries requires ongoing work," they write.

"A large amount of lost health comes from people who have a blood pressure below 140 mm Hg," Roth added. "Recent strong evidence from the SPRINT clinical trial suggests that some of these individuals would benefit from blood-pressure–lowering medications.

"We do not yet have strong evidence that everyone should be on blood-pressure medications at [135 mm Hg], so other interventions—for example, lifestyle modification or healthy lifestyle earlier in life (primordial prevention)—could be important paths to reducing burden in that range."

This research was supported by funding from the Bill and Melinda Gates Foundation. Forouzanfar and Roth have no relevant financial relationships. Disclosures for the coauthors are listed in the paper. Huffman reports receipt of grants from the World Heart Federation and the JR Alberts Foundation and travel support from the American Heart Association outside the editorial. Dr Lloyd-Jones reports no relevant financial relationships.

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