Decline in stroke deaths linked to hypertension control

The number of stroke deaths decreased considerably throughout the 20th century, and the American Heart Association/American Stroke Association wrote in a scientific statement published in the January 2014 issue of Stroke that the trend is the result of the aggressive management of risk factors.

Calling the decline “a major public health and clinical medicine success story,” the joint writing panel wrote that controlling hypertension likely played a major role. They used a variety of sources to analyze the mortality trends, including literature reviews, guidelines and reports.

Once the third leading cause of death in the U.S., stroke is now the fourth, replaced at its former position by lung disease. However, the rise in pulmonary-related mortality is not a cause of this ranking change; rather, it is an actual decline in stroke mortality, wrote the panel, led by Daniel T. Lackland, DrPH.

Starting in 1900, the number of deaths from stroke decreased from more than 150 per 100,000 to 50 per 100,000 in the late 1960s. Beginning in the 1970s, the mortality rate declined to 5 percent per year.

Lackland and his colleagues attributed much of the decline to better control of hypertension.

“[T]he US age-adjusted stroke mortality rate reduction from 88 per 100,000 in 1950 to 23 per 100,000 in 2010, with consistent reductions in mortality rates for all age, racial/ethnic, and sex groups in the United States, as well as other countries, is consistent with HBP [high blood pressure] recognition and reduction campaigns initiated during the same period,” they wrote. In fact, the decline was steepest after the first tolerable antihypertensive therapy was introduced in the 1960s. Analysis revealed that the average systolic blood pressure decreased from 131 mm Hg in 1960 to 122 in 2008, and the decline was consistent across age groups. 

The investigators also noted that treatment and control of diabetes and hyperlipidemia also played some role in the decline of stroke deaths, but interventions aimed at these risk factors came about more recently, so it is not yet clear how much they contributed to the decline.

Other factors such as atrial fibrillation, smoking cessation and the use of tissue plasminogen activator (tPA) may also have some impact, but more research is needed to determine how big that impact is.

The authors said they are confident stroke mortality will continue to decline.

“With the implementation of evidence-based primary, secondary and tertiary stroke prevention strategies, these trends should continue,” they wrote.