Stroke incidence, mortality rates decrease globally but overall numbers still high

Despite a slight decrease in the worldwide incidence and mortality rates for stroke between 1990 and 2019, the overall numbers remain high, according to study results published in Neurology.

The numbers are especially high in high- and middle-income countries, researchers noted.

“Studies have reported the global ischemic stroke burden based on analyses of the previous [Global Burden of Disease] GBD,” Quanquan Ding, PhD, of Hwa Mei Hospital at the University of Chinese Academy of Sciences, and colleagues wrote. “A study of the global burden of stroke has focused on the total percentage change of ischemic stroke burden during 1990 [to] 2019. However, none has calculated the global estimated annual percentage changes (EAPCs) in ischemic stroke burden by performing linear regression of data from the GBD 2019 datasets.”

The investigators sought to assess global, regional and national stroke burdens and determine correlations with sex, age and social development index (SDI) by extracting data from the GBD 2019 datasets. They estimated EAPCs to examine trends in ischemic stroke related to incidence rate, mortality and disability-adjusted life years (DALY), stratifying measures based on sex, region, country, age and SDI.

Results showed a decrease in the global age-standardized incidence rate (ASIR) between 1990 and 2019. Researchers noted an EAPC of –0.43 (95% CI, –0.54 to –0.32). They reported significantly higher ASIR, age-standardized death rate (ASDR) and age-standardized DALY rates due to ischemic stroke in high-middle and middle SDI regions compared with other SDI regions.

On the regional level, the highest ASIR of ischemic stroke in 2019 and the largest increase in the ASIR between 1990 and 2019 occurred in East Asia. On the national level, the most significant increases in the ASIR of ischemic stroke occurred in Egypt (EAPC = 1.4; 95% CI, 1.27-1.52) and China (EAPC = 1.1; 95% CI, 1-1.2). On the global level, individuals with increasing age, particularly women aged 50 to 69 years or older, had an increase in ischemic stroke incidence. Ding and colleagues noted a decrease in the global ASDR between 1990 and 2019, with an EAPC of –1.63 (95% CI, –1.72 to –1.53). Southern sub-Saharan Africa, Eastern sub-Saharan Africa and Southeast Asia exhibited the most significant ASDR and age-standardized DALY rate increases.

“The strength of this study is its systematic use of data (from the GBD 2019 study) and methods to estimate the burden of ischemic stroke in regions throughout the world from 1990 to 2019,” the researchers wrote. “The GBD 2019 is an unparalleled source of up-to-date data that also provides access to its data sources, research methods and results. Moreover, its original estimates of disease burdens are revised based on new data and improved methods to afford current estimates of disease burdens.”

Ding and colleagues also noted several measurement limitations in the estimation of the cause-specific mortality and non-fatal burden of ischemic stroke from the GBD data.

“For example, the quality and accuracy of GBD data for some underdeveloped regions, such as Africa and Latin America, cannot be guaranteed, because many countries in these regions did not have reliable mortality information systems and population-based ischemic stroke registries during the GBD survey period,” they wrote.