Between 1990 and 2015, the rate of systolic blood pressure of at least 110 to 115 mm Hg and of 140 mm Hg or higher significantly increased, according to an analysis from 195 countries and territories.

During that 25-year period, the estimated rate of annual deaths and disability-adjusted life years (DALYs) in both groups also increased. DALYs included deaths and nonfatal burden.

In 2015, an estimated 3.5 billion adults had a systolic blood pressure of at least 110 to 115 mm Hg, while an estimated 874 million adults had a systolic blood pressure of 140 mm Hg or higher. The researchers defined hypertension as a systolic blood pressure of 140 mm Hg or higher.

Lead researcher Mohammad H. Forouzanfar, PhD, of the University of Washington, and colleagues published their results online in JAMA on Jan. 10.

“These results support the model assumption that elevated [systolic blood pressure] is a modifiable risk factor for mortality even though the precise subpopulation and [systolic blood pressure] target for blood pressure–lowering medications remains less clear,” the researchers wrote. “The purpose of this study was to estimate the full extent of health burden lost related to elevated [systolic blood pressure] and not to determine the optimum [systolic blood pressure] level for the current population.”

This analysis was part of the Global Burden of Disease, Injuries, and Risk Factor (GBD) study, which is a descriptive meta-analysis of trials. The researchers noted the data are projections for a population and should be assessed based on the availability of data, the uncertainty of pooled estimates and the models used.

The GBD included 844 studies from 154 countries that were published from 1980 to 2015. In all, 8.69 million adults participated.

Between 1990 and 2015, the rate of systolic blood pressure of at least 110 to 115 mm Hg increased from 73,199 to 81,373 per 100,000 persons, while the rate of systolic blood pressure of at least 140 mm Hg increased from 17,307 to 20,526 per 100,000 persons.

During those 25 years, the estimated annual deaths for systolic blood pressure of at least 110 to 115 mm Hg increased from 135.6 deaths to 145.2 deaths per 100,000, while the estimated annual deaths for systolic blood pressure of 140 mm Hg or higher increased from 97.9 deaths to 106.3 deaths per 100,000.

Meanwhile, the projected DALYs associated with a systolic blood pressure of at least 110 to 115 mm Hg increased from 148 million to 211 million, while the rate of DALYs associated with a systolic blood pressure of 140 mm Hg or higher increased from 5.2 million to 7.8 million.

Ischemic heart pressure caused the largest number of systolic blood pressure-related deaths (4.9 million), followed by hemorrhagic stroke (2.0 million) and ischemic stroke (1.5 million).

The U.S., China, India, Russia and Indonesia accounted for more than half of the global DALYs associated with a systolic blood pressure of at least 110 mm Hg to 115 mm Hg,

The researchers noted that a systolic blood pressure of at least 110 to 115 mm Hg was associated with more than 10 million deaths and 212 million DALYs in 2015, which was a 1.4-fold increase since 1990. They added that a systolic blood pressure of at least 110 to 115 mm Hg was the leading risk factor for preventable death in 2015, according to the GBD.

The study had a few limitations, according to the researchers, including that they did not assess the burden of high diastolic blood pressure. They also mentioned that 41 countries had no survey data, so they based their estimates of blood pressure levels on spatiotemporal Gaussian process regressional statistical models.

In addition, they estimated the burden with systolic blood pressure only for adults who were 25 years old or older except for hypertensive heart disease, when they included adults of all ages. Further, they assumed the relative risks for each outcome were generalizable for all patient populations and assumed that the relative risk of each 10-mm increment of systolic blood pressure was the same from 115 mm Hg to above 200 mm Hg.

“While acknowledging these limitations, this study was based on the largest available set of data and applied the same methods to previous years to provide a consistent analysis of time trends from 1990 to 2015,” the researchers wrote.