Chapter 1 – Stroke: The Size of the Problem




Abstract




In the year 2010, an estimated 16.9 million strokes occurred worldwide at an incidence rate of 258 per 100,000 persons per year. Approximately 70% of these strokes occurred in low- and middle-income countries. The 16.9 million incident strokes were added to a pool of 33 million prevalent stroke survivors. There were 5.9 million deaths and 102 million disability-adjusted life-years (DALYs) lost due to stroke in 2010, making stroke the second leading cause of death and the third leading cause of DALYs worldwide. In the preceding two decades, between 1990 and 2010, the incidence rate of stroke remained stable but the absolute number of incident strokes increased by 68%, the prevalence rate increased modestly yet the absolute number of stroke survivors nearly doubled, the rate of DALYs lost due to stroke decreased but the absolute number of DALYs lost increased by 12%, and the mortality rate fell but the absolute number of stroke-related deaths increased by 26%. Most of the burden of stroke is in low-income and middle-income countries, which bear 63% of incident ischaemic strokes and 80% of haemorrhagic strokes. The average age of incident ischaemic and haemorrhagic strokes was 6 years younger in low- and middle– than high–income countries.





Chapter 1 Stroke: The Size of the Problem



Graeme J. Hankey


The global and regional burden of stroke during 1990–2015 has been estimated by the Global Burden of Disease (GBD) studies of 2010, 2013, and 2015 (Krishnamurthi et al., 2013, 2015; Feigin et al., 2014, 2015; GBD 2015 Neurological Disorders Collaborator Group, 2017).


The GBD 2010 study group undertook a systematic review which identified 119 relevant studies (58 from high-income countries [HIC] and 61 from low- and middle-income countries [LMIC]) that were published between 1990 and 2010 and from which regional and country-specific estimates of the incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) lost by age group (<75 years, ≥75 years, and in total) and country income level of first-ever ischaemic and haemorrhagic stroke in all 21 regions of the world for 1990, 2005, and 2010 could be calculated (Feigin et al., 2014). Pathological subtypes of stroke were confirmed by brain imaging or autopsy in at least 70% of cases.


The GBD estimates of stroke incidence in all regions were therefore obtained using a systematic approach which allows comparison across disease states. Complementary estimates of stroke incidence, based on epidemiological studies of stroke incidence using ideal methods, and also adjusted to the World Health Organization (WHO) world population figures, are provided by Thrift and Kim and colleagues (2020).



Incidence


In 2010, the age-standardized incidence rate of stroke was 258 (234–284) per 100,000 person-years (Feigin et al., 2014) (Table 1.1).




Table 1.1 Age-adjusted annual incidence and mortality rates (per 100,000 person-years), prevalence (per 100,000 people), and disability-adjusted life-years (DALYs) lost (number, and per 100,000) for all stroke, ischaemic stroke, and haemorrhagic stroke, in 1990, 2005, 2010, and 2015























































































































All Stroke 1990 2005 2010 2015 Change from 1990–2015
Number of events Rate (95% CI) per 100,000 Number of events Rate (95% CI) per 100,000 Number of events Rate (95% CI) per 100,000 Number of events Rate (95% UI) per 100,000 Number of events Rate (95% UI) per 100,000
Incidence 10,078,935 251 (230–273) 14,734,124 256 (232–284) 16,894,536 258 (234–284) Not reported Not reported 68%↑ (to 2010) 12% (6–17%) ↓ HIC (to 2010)
12% (–3–22%) ↑ LMIC (to 2010)
Prevalence 17,915,338 435 (389–497) 28,495,582 490 (437–558) 33,024,958 502 (451–572) 42,431,000 627 (621–631) 59.2% (58–60%) ↑ 9.8% (9–10%) ↓
(42.068 m –42.767 m)
DALYs lost 86,010,384 2063 (1950–2280) 101,951,696 1750 (1569–1831) 102,232,304 1554 (1374–1642) 118,627,000 (114.862 m –111.627 m) 1777 (1721–1835) 21.7% (18–26%)↑ 32.3% (30–34%) ↓
Deaths 4,660,449 117 (112–130) 5,684,970 99 (89–104) 5,874,182 88 (80–94) 6,326,000 101 (99–104) 36.4% (32–41%) ↑ 30% (28–32%) ↓
(6.175 m – 6.493 m)
















































































































Ischaemic stroke
Incidence 7,238,758 181 (167–196) 10,097,297 175 (160–192) 11,569,538 176 (161–192) 37% ↑ 13% (6–18%) ↓ HIC
6% (–7–18%) ↑ LMIC
DALYs lost 32,128,220 796 (734–906) 38,571,908 668 (617–774) 39,389,408 598 (560–692) 18% ↑ 34% (16–36%) ↓ HIC
17% (–11–19%) ↓ LMIC
Mortality 2,241,077 58 (54–64) 2,701,873 47 (44–54) 2,835,419 42 (40–49) 21% ↑ 37% (19–39%) ↓ HIC
14% (9–19%) ↓ LMIC





































































































Haemorrhagic stroke
Incidence 2,840,177 69 (62–77) 4,636,828 80 (71–92) 5,324,997 82 (72–93) 47% ↑ 18.5% ↑ globally
8% (1–15%) ↓ HIC
22% (5–30%) ↑ LMIC
DALYs lost 53,882,164 1267 (1068–1484) 63,379,792 1081 (935–1234) 62,842,896 956 (828–1104) 14% ↑ 39% (32–44%) ↓ HIC
25% (7–38%) ↓ LMIC
Mortality 2,419,372 60 (51–70) 2,983,097 52 (45–59) 3,038,763 46 (40–53) 20% ↑ 38% (32–43%) ↓ HIC
23% (–7–36%) ↓ LMIC


Source: Adapted from Krishnamurthi et al., 2013, 2014; Feigin et al., 2014; Bennett et al., 2014, and GBD 2015 Neurological Disorders Collaborator Group, 2017. CI: confidence interval. HIC: high-income countries. LMIC: low- and middle-income countries. UI: uncertainty interval.

The absolute number of people who experienced a first stroke was 16.9 million in 2010; 68.6% were resident in LMIC and 62% were aged younger than 75 years (Feigin et al., 2014) (Table 1.1). In 2013, there were 10.3 million new strokes (67% ischaemic stroke [IS]) (Feigin et al., 2015).



Ischaemic Stroke


In 2010, the age-standardized incidence of IS was 176 (161–192) per 100,000 person-years (Bennett et al., 2014) (Table 1.1).


In 2010, there were approximately 11,569,000 incident IS events (63% in LMIC) (Bennett et al., 2014).



Haemorrhagic Stroke


In 2010, the overall age-standardized incidence rate of haemorrhagic stroke (HS) (intracerebral and subarachnoid haemorrhage) was 81.52 (95% confidence interval [CI]: 72.27–92.82) per 100,000 person-years globally.


In 2010, there were 5.3 million cases of HS; 80% were in LMIC (Krishnamurthi et al., 2013, 2014).


There were significant regional differences in incidence rates of HS, with the highest rates in LMIC regions such as sub-Saharan Africa and East Asia, and lowest rates in high-income North America and Western Europe.


The overall age-standardized incidence rates of HS per 100,000 person-years were 48.41 (95% CI: 45.44– 52.13) in HIC and 99.43 (95% CI: 85.37–116.28) in LMIC. Hence, LMIC had a 40% higher incidence of HS than did HIC.



Trends in Stroke Incidence Rates


From 1990 to 2010, the age-standardized incidence of stroke per 100,000 person-years remained fairly stable, being 251 (95% CI: 230–273) in 1990 and 258 (95% CI: 234–284) in 2010 (Feigin et al., 2014) (Table 1.1).


However, from 1990 to 2010, the absolute number of people with a first stroke increased significantly by 68%, from 10 million to 16.9 million.


From 1990 to 2010, the age-standardized incidence of stroke per 100,000 person-years significantly decreased by 12% (95% CI: 6–17) in HIC, and increased by 12% (95% CI: –3–22) in LMIC, albeit non-significantly.



Ischaemic Stroke


From 1990 to 2010, the age-standardized incidence of IS per 100,000 person-years remained fairly stable, being 181 (95% CI: 167–196) in 1990 and 176 (95% CI: 161–192) in 2010


From 1990 to 2010, there was a significant increase in the absolute number of people with incident IS from 7.2 million to 11.6 million (37% increase).


Age-standardized IS incidence in HIC declined by about 13% (95% uncertainty interval [UI]: 6–18%). However, in LMIC there was a modest 6% increase in the age-standardized incidence of IS (95% UI: –7–18%).



Haemorrhagic Stroke


The age-standardized incidence of HS increased by 18.5% worldwide between 1990 and 2010, from 69 (62–77) to 82 (72–93) per 100,000 person-years.


From 1990 to 2010, there was a 47% increase worldwide in the absolute number of HS cases, from 2.8 million to 5.3 million.


In HIC, there was a reduction in incidence of HS by 8% (95% CI: 1–15%) in the past 2 decades. However, in low-income and middle-income countries there was a significant increase in the incidence of HS by 22% (95% CI: 5-30%), which is one rate that has increased over the past two decades, particularly in people younger than 75 years (19% increase in HS in past two decades, 95%CI: 5–30% increase).



Prevalence


In 2010, the prevalence of stroke survivors was 502 (451–572) per 100,000 people and the absolute number of stroke survivors was 33 million.


In 2015, the prevalence of stroke survivors was 627 (95% UI: 621–631) per 100,000 people and the absolute number of stroke survivors was 42.431 million (95% UI: 42.068–42.767 million) (GBD 2015 Neurological Disorders Collaborator Group, 2017).



Ischaemic Stroke


In 2013, in younger adults aged 20–64 years, the global prevalence of IS was 7.258 million cases (95% UI: 6.996–7.569 million) (Krishnamurthi et al., 2015).

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Mar 22, 2021 | Posted by in NEUROLOGY | Comments Off on Chapter 1 – Stroke: The Size of the Problem
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