New global data reveals that the burden of stroke is increasing, particularly in low- and middle-income countries, with increasing incidence among young people and widening regional disparities.
Research: Global, regional and national stroke burden and risk factors, 1990-2021: Systematic analysis for the Global Burden of Disease Study 2021. Image credit: illustrissima/Shutterstock.com
In a recent study published in The Lancet Neurology, a group of researchers analyzed the global burden of stroke and its associated risks from 1990 to 2021 to inform evidence-based care and resource allocation. Provided the latest estimates for regions and countries.
background
According to the Global Burden of Disease (GBD) study, the incidence of cardiovascular diseases, including stroke, has nearly doubled from 271 million people in 1990 to 523 million people in 2019.
Mortality rates from cardiovascular disease declined in the second half of the 20th century, but progress has slowed, and mortality rates have increased since 2010 in some countries, such as Mexico, the United Kingdom (UK), and the United States (USA). I’m doing it.
Stroke rates are also increasing in people under 55, as risk factors such as high blood pressure and obesity skyrocket. Further research is essential to track trends, evaluate interventions, and develop global health strategies for stroke prevention and management.
About research
The GBD 2021 study on stroke burden and risk factors employed an established methodology consistent with previous estimates.
Stroke is defined based on World Health Organization (WHO) clinical criteria and includes ischemic stroke (blockage of blood flow to the brain), intracerebral hemorrhage (bleeding within the brain), and subarachnoid hemorrhage (bleeding between the brains). ) are classified into three types. covering).
Vital registration and monitoring data were used to create independent models for each stroke type to ensure accurate modeling. Stroke incidence and prevalence were modeled using DisMod-MR 2.1, a Bayesian software that considers various disease parameters.
Mortality estimates were derived using cause of death ensemble modeling (CODEm). Data for analysis included a wide range of sources, including vital registration, oral autopsy, and risk factor exposure data.
Population attributable fractions (PAFs) of disability-adjusted life years (DALYs) were calculated to assess the stroke burden attributable to 23 risk factors. These factors were categorized into four categories: environmental risks, dietary risks, behavioral risks, and metabolic risks.
This analysis also considered interactions between risk factors and accounted for mediating effects in the overall calculation.
This study utilized meta-regression techniques to pool relative risk data to estimate the potential reduction in stroke burden if exposure to risk factors was at optimal levels. This comprehensive approach allowed for stratification of estimates by region, age, gender, and socio-demographic index (SDI).
Research results
Global stroke statistics for 2021 reveal 93.8 million stroke survivors, 11.9 million new stroke cases, 7.3 million stroke-related deaths, and 160.5 million DALYs lost due to stroke. This accounted for 10.7% of all deaths and 5.6% of total all-cause DALYs. .
Stroke is the third leading cause of death after ischemic heart disease and coronavirus disease 2019 (COVID-19), and the fourth leading cause of DALYs. The majority of the stroke burden occurs in low- and middle-income countries (LMICs), including 83.3% of new strokes and 87.2% of stroke deaths, highlighting significant geographic disparities. .
The burden of stroke varies widely by region. For example, the lowest age-standardized stroke incidence was in Luxembourg (57.7 per 100,000 people), while the Solomon Islands had the highest (355.0 per 100,000 people).
Similarly, the lowest stroke mortality rate was in Singapore (14.2 per 100,000 people) and the highest in North Macedonia (277.4 per 100,000 people). Significant differences in stroke burden are observed between high-income and low-income regions, with Central Asia, East Asia, and sub-Saharan Africa facing the highest stroke burden. In contrast, high-income regions such as North America and Australia had the lowest rates.
Regarding the types of pathological strokes, ischemic stroke was the most common, accounting for 65.3% of all new strokes in 2021, followed by intracerebral hemorrhage (28.8%) and subarachnoid hemorrhage (5.8%). However, even though ischemic stroke is the most prevalent, the proportion of total DALYs due to intracerebral hemorrhage (49.6%) was higher than ischemic stroke (43.8%).
Subarachnoid hemorrhage caused 6.6% of all stroke-related DALYs. These types also showed clear geographic and socio-economic trends. For example, ischemic strokes accounted for 74.9% of new strokes in high-income countries, but only 63.4% in LMICs, where intracerebral hemorrhage was more common.
From 1990 to 2021, age-standardized stroke incidence, prevalence, mortality, and DALY rates decreased globally, with the most significant decreases occurring in people aged 70 years and older.
However, population growth and aging led to an increase in the number of strokes, deaths, and DALYs during this period. The incidence of stroke among people under 70 years of age also showed an upward trend. The decline in stroke rates has slowed in recent years, particularly since 2015, with stroke rates plateauing or even increasing in some regions.
conclusion
In summary, in 2021, stroke became the second leading cause of death and third leading cause of DALYs among non-communicable diseases worldwide. Stroke burden is disproportionately high in LMICs and low-SDI regions, with intracerebral hemorrhage occurring nearly twice as often in LMICs compared to high-income countries.
This difference may be due to the higher prevalence of hypertension and poorer hypertension control in LMICs. Although age-standardized stroke incidence has decreased globally since 1990, incidence, prevalence, and DALYs have increased in Southeast Asia, East Asia, and Oceania since 2015.
