Factors Influencing the Decline in Stroke Mortality : A Statement from the American Heart Association/American Stroke Association

Abstract

Background and Purpose

Stroke mortality has been declining since the early twentieth century. The reasons for this are not completely understood, although the decline is welcome. As a result of recent striking and more accelerated decreases in stroke mortality, stroke has fallen from the third to the fourth leading cause of death in the United States. This has prompted a detailed assessment of the factors associated with this decline. This review considers the evidence of various contributors to the decline in stroke risk and mortality and can be used in the design of future interventions regarding this major public health burden.

Methods

Writing group members were nominated by the committee chair and co-chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council’s Scientific Statement Oversight Committee and the AHA’s Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize evidence and indicate gaps in current knowledge. All members of the writing group had the opportunity to comment and approved the final version of this document. The document underwent extensive AHA internal peer review, Stroke Council Leadership review and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee.

Results

The decline in stroke mortality over the past decades represents a major improvement in population health and is observed for both genders, and all race and age groups. In addition to the overall impact on fewer lives lost to stroke, the major decline in stroke mortality seen among individuals less than 65 years of age represents a reduction on years of potential life lost. The decline in mortality results from reduced stroke incidence and lower case fatality rates. These significant improvements in stroke outcomes are concurrent with cardiovascular risk factor control interventions. While it is difficult to calculate specific attributable risk estimates, the hypertension control efforts initiated in the 1970s appears to have had the most substantial influence on the accelerated stroke mortality decline. Although implemented later in the time period, diabetes and dyslipidemia control and smoking cessation programs, particularly in combination with hypertension treatment, also appear to have contributed to the stroke mortality decline. Telemedicine and stroke systems of care, while showing strong potential effects, have not been in place long enough to show their influence on the decline. Other factors had probable effects, but additional studies are needed to determine their contributions.

Conclusion

The decline in stroke mortality is real and represents a major public health and clinical medicine success story. The repositioning of stroke from 3 ^rd to 4 ^th leading cause of death is the result of true mortality decline and not an increase of chronic lung disease mortality, which is now the 3 ^rd leading cause of death in the United States. There is strong evidence the decline can be attributed to a combination of interventions and programs based on scientific findings and implemented with the purpose to reduce stroke risks, the most likely being improved hypertension control. Thus, research studies and the application of their findings to develop intervention programs have improved the health of the population. The continued application of aggressive evidence-based public health programs and clinical interventions are expected to result in further declines in stroke mortality.