Antihypertensive therapy may be the main reason that stroke fatalities have decreased dramatically in the United States during the past 50 years, according to research conducted by the American Heart Association. The group’s study was published December 5, 2013, in Stroke.
Despite an aging and overweight population, “the accelerated decline in stroke mortality that began in the 1970s is consistent with the aggressive hypertension treatment and control strategies implemented in that period. ... The decrease in blood pressure with drug therapy ... appears to be the major determinant of reduction in the risk of stroke and stroke deaths,” said Daniel Lackland, PhD, Professor of Epidemiology at the Medical University of South Carolina in Charleston, and lead author of the study.
Other factors that have contributed to the decline in stroke mortality include statins, diabetes drugs, public-health efforts, increased research, improved imaging, and more rapid and effective stroke treatment. In recent years, more people have lost weight, reduced their salt intake, and begun to eat and smoke less.
These changes have helped to reduce the stroke mortality rate from 88/100,000 in 1950 to 23/100,000 in 2010—a reduction that is consistent among all races, ages, and genders. But the strongest evidence suggests that hypertension control is the major reason for this reduction in mortality, according to the authors.
“Although the decline in stroke mortality in the United States started at the beginning of the 20th century, decades before hypertension treatment, the slope of the decline in mortality accelerated significantly after the introduction of tolerable antihypertensive drug therapy in the 1960s,” said Dr. Lackland. Stroke is now the fourth leading cause of death in the United States, instead of the third, and the incidence of recurrent and initial strokes has declined. Europe has had a similar decline.
Although great racial disparities still exist in stroke mortality, particularly between Caucasians and African Americans, “the decline in stroke mortality for all racial/ethnic groups has reduced the magnitude of the racial/ethnic gap in stroke mortality risks and likewise the variation in stroke mortality by geographic area, with particular emphasis in the Stroke Belt,” said Dr. Lackland.
“The decline is real, not a statistical fluke or the result of more people dying of lung disease, the third leading cause of death,” he added. The decline does not result from changes in billing codes, diagnostic improvements, death certificate causes of death, or other factors that the investigators considered. Instead, the decline is “one of the major public health successes of the past 50 years,” said Dr. Lackland.
The investigators’ findings are based on literature reviews, morbidity and mortality reports, clinical and public health guidelines, and expert opinion.
“Increased application of advanced neuroimaging ... might improve the diagnosis of milder, less-fatal strokes over time,” said Dr. Lackland. “This [improvement] would result in an apparent decline in the stroke case-fatality rate, solely as a result of improved detection. However, this [change] should not result in a change in stroke mortality over time unless technological advances improve the diagnosis of more severe, fatal strokes also, which seems unlikely.”
—M. Alexander Otto