Stroke

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What is stroke?

Stroke occurs when a blood vessel supplying blood to the brain either suddenly becomes blocked (ischaemic stroke) or ruptures and begins to bleed (haemorrhagic stroke).

Either may result in part of the brain dying, leading to impairment that can affect a range of activities such as speaking, thinking, movement and communication. Stroke is often fatal.

A condition related to stroke is transient ischaemic attack (TIA). TIA occurs when the blood supply to the brain is blocked temporarily. The signs are the same as for a stroke, but they disappear within a short time, and there is no evidence of damage on brain imaging. TIA is an important predictor of stroke.

Risk factors for stroke include tobacco smoking, high blood pressure, abnormal blood lipids, TIA, atrial fibrillation, diabetes and other heart disease.

Stroke is sometimes referred to as cerebrovascular disease, although cerebrovascular disease is a broader category of diseases which include stroke and other disorders of the blood vessels supplying the brain or its covering membranes. Stroke is the most common form of cerebrovascular disease.

How many Australians have had a stroke?

In 2018, an estimated 387,000 Australians aged 15 and over (1.3% of the population) had experienced a stroke at some time in their lives, based on self-reported data from the ABS Survey of Disability, Ageing and Carers (ABS 2019).

Age and sex

After adjusting for age, the prevalence of stroke was:

  • higher in males (1.6%) than females (1.1%)
  • more common in older age groups—over 2 in 3 (71%) people who had a stroke were aged 65 and over. Proportions were highest for those aged 85 and over—almost 3 times as high as for those aged 65–74 (13.6% and 4.6%) (Figure 1).

Figure 1: Prevalence of self-reported stroke among persons aged 15 and over, by age and sex, 2018

The bar chart shows the prevalence of self-reported stroke by age group in 2018. Rates were highest among men and women aged 85 and over (16.0% and 12.3%).

Variation among population groups

Aboriginal and Torres Strait Islander people

Limited national information on the occurrence of stroke is available for the Indigenous population, with under-identification in hospital and death data and small case numbers often hampering accurate estimates (Katzenellenbogen et al. 2011). However, studies in a number of jurisdictions have found rates to be higher than for the non-Indigenous population, including:

  • a first-ever stroke incidence rate of 116 per 100,000 population in South Australia in 2009–2011—1.7 times as high as for the non-Indigenous population (Balabanski et al. 2018)
  • a first-ever stroke incidence rate of 307 per 100,000 population in the Northern Territory in 1999–2011—2.2 times as high as for the non-Indigenous population (You et al. 2015)
  • stroke incidence rates of 377 for Indigenous males and 341 for Indigenous females in Western Australia in 1997–2002—2.6 and 3.0 times as high as for the non-Indigenous population (Katzenellenbogen et al. 2011).

Socioeconomic group

Based on the 2018 Survey of Disability, Ageing and Carers, the age-standardised prevalence of stroke among people aged 15 and over living in the lowest socioeconomic areas (1.8%) was more than twice as high than for those than in the highest areas (0.8%).

Remoteness area

Based on the 2018 Survey of Disability, Ageing and Carers, for both men and women, there were no statistically significant differences in the age-standardised prevalence of stroke across remoteness areas (Figure 2).

Figure 2: Prevalence of self-reported stroke among persons aged 15 and over, by population group and sex, 2018

The horizontal bar chart shows that the prevalence of self-reported stroke in 2017–18 was higher among people living in socioeconomically disadvantaged areas, but did not vary significantly by remoteness areas.

Stroke events

There are no national data sources on the annual number of strokes. However, a related measure can be used as an estimate—the number of stroke events—developed by the AIHW using unlinked hospital and deaths data.

The number of stroke events includes new and recurrent strokes.

In 2018, there were an estimated 38,600 stroke events in Australia—more than 100 every day. The rate of stroke events was 154 per 100,000 population.

Age and sex

In 2018, there were an estimated 20,200 stroke events among males and 18,400 among females.

Rates of stroke events:

  • were higher in males than females (age-standardised rates of 147 and 109 per 100,000 population)
  • increased with age, with the rate of the 85 and over age group (2,150 per 100,000 population) more than twice the rate of the 75–84 year age group (900 per 100,000 population), and almost 6 times the rate of the 65–74 year age group (360 per 100,000 population) (Figure 3).

Figure 3: Stroke events, by age and sex, 2018

The bar chart shows the prevalence of stroke events by age group in 2018. Rates were highest among men and women aged 85 and over (2,099 and 2,173 per 100,000 population).

Trends

The rate of stroke events fell by one quarter (25%) between 2001 and 2018, from 169 to 127 events per 100,000 population.

The decline in rates was slightly greater for females (26%) than males (24%) (Figure 4). Since 2013, however, stroke event rates have levelled for both males and females.

Figure 4: Stroke events, by sex, 2001–2018

The line chart shows the decline in age-standardised rates of stroke events between 2001 and 2018, from 193 to 147 per 100,000 population for males and 148 to 109 for females.

 Transient ischaemic attack

Transient ischemic attack (TIA) is a condition related to stroke. It is a temporary blockage of the blood supply to the brain, often lasting only a few minutes, and producing stroke-like symptoms that disappear within a short time.

Unlike stroke, there is no permanent damage to the brain, with no remaining symptoms, and no evidence of damage on brain imaging. TIA is, however, an important predictor of stroke—after a TIA, the risk of stroke is much higher (Stroke Foundation 2021).

  • In 2018–19 there were 18,300 presentations to public hospital emergency departments with a principal diagnosis of TIA—two-thirds (12,400 or 68%) were subsequently admitted to hospital.
  • There were 16,400 admissions to hospital with a principal diagnosis of TIA—a rate of 65 per 100,000 population. Male rates were higher than female rates (age-standardised rates of 59 and 49 per 100,000 population).
  • Around 6.4% (1,040) of TIA admissions had an additional diagnosis of atrial fibrillation.

One quarter (4,050 or 25%) of TIA admissions were on a same-day basis. The average length of stay in hospital for all TIA admissions was 2.9 days.

Hospitalisations

There were around 67,700 hospitalisations where stroke was recorded as the principal diagnosis in 2018–19.

This represents 0.6% of all hospitalisations, and 11% of all cardiovascular disease (CVD) hospitalisations in Australia.

Of these, 39,600 (58%) required acute care, and 28,100 (42%) were for rehabilitation and other types of care.

Age and sex

In 2018–19, where stroke was recorded as the principal diagnosis, hospitalisation rates:

  • were 1.5 times higher for males than females (age-standardised rates of 269 and 183 hospitalisations per 100,000 population)
  • increased with age, with rates for males and females highest in those aged 85 and over (2,900 and 2,600 per 100,000 population)―around 1.5 times as high as males aged 75–84 (1,900 per 100,000) and 1.9 times as high as females aged 75–84 (1,300 per 100,000) (Figure 5)
  • close to half (49%) of all stroke hospitalisations occurred among persons aged 75 and over.

Figure 5: Stroke hospitalisation rates, principal diagnosis, by age and sex, 2018–19

The bar chart shows stroke hospitalisation rates by age groups in 2018–19. Rates were highest among men and women aged 85 and over (2,877 and 2,554 per 100,000 population).

Trends

  • Between 2000–01 and 2018–19, the number of acute care stroke hospitalisations increased by 35% for males, and 12% for females.
  • The age-standardised rate of hospitalisation for acute care stroke fell by 22%, from 169 to 131 per 100,000 population. Rates fell by 21% for males (from 197 to 156 per 100,000 population) and 26% for females (from 145 to 108 per 100,000 hospitalisations) (Figure 6).
  • Hospitalisation rates fell for most age groups, but increased for those age 45–54 years, from 82 to 95 per 100,000 hospitalisations.

Figure 6: Acute care stroke hospitalisation rates, principal diagnosis, by sex, 2000–01 to 2018–19

The line chart shows the decline in age-standardised rates of acute care stroke hospitalisations between 2000–01 and 2018–19, from 197 to 156 per 100,000 population for males, and from 145 to 108 for females.

Variation among population groups

Aboriginal and Torres Strait Islander people

In 2018–19, there were around 1,500 hospitalisations with a principal diagnosis of stroke among Aboriginal and Torres Strait Islander people.

After adjusting for differences in the age structure of the populations:

  • the rate among Indigenous Australians was 1.5 times as high as the non-Indigenous rate (329 and 217 per 100,000 population)
  • the disparity between Indigenous and non-Indigenous Australians was greater for females than males—1.7 times as high for females (307 and 177 per 100,000 population) and 1.3 times as high for males (350 and 260 per 100,000 population) (Figure 7).

Socioeconomic group

In 2018–19, age-standardised stroke hospitalisation rates for people living in the lowest and highest socioeconomic areas were similar—235 and 217 per 100,000 population (Figure 7).

Remoteness area

In 2018–19, age-standardised stroke hospitalisation rates for people living in Remote and very remote areas were around 10% higher than for people living in Major cities (248 and 226 hospitalisations per 100,000 population) (Figure 7).

Figure 7: Stroke hospitalisation rates, principal diagnosis, by population group and sex, 2018–19

The horizontal bar chart shows that stroke hospitalisation rates in 2018–19 were higher among Indigenous Australians and people living in Remote and very remote areas, but did not differ significantly by socioeconomic area.

Deaths

In 2019, stroke was the underlying cause of 8,400 deaths (5.0% of all deaths and 20% of CVD deaths).

Stroke was one of the 5 leading causes of death in Australia—on average, 23 Australians died of stroke each day in 2019.

Age and sex

In 2019, stroke death rates:

  • were similar for males and females (age-standardised rates of 24 and 25 per 100,000 population)
  • were higher for males than females in each age group, except for 85 and over, where rates were higher among females than males (969 and 739 per 100,000 population)
  • increased with age, with over half (54%) of all stroke deaths occurring in those aged 85 and over, where stroke death rates were 4 times as high for males and 6 times as high for females aged 75–84 (179 and 172 per 100,000 population) (Figure 8).

Figure 8: Stroke death rates, by age and sex, 2019

The bar chart shows stroke death rates by age groups in 2019. Rates were highest among men and women aged 85 and over (739 and 969 per 100,000 population).

Trends

The number and rate of stroke deaths declined substantially between 1980 and 2019:

  • the number of stroke deaths declined by 30%, from around 12,100 to 8,400
  • the age-standardised stroke death rate declined by three-quarters (76%), falling from 104 to 25 deaths per 100,000 population. Stroke death rates declined in a similar fashion for males and females (Figure 9).

Falling stroke death rates have been driven by a number of factors, including improvements in risk factors such as lower rates of tobacco smoking, an increased use of blood pressure–lowering drugs, treatment to prevent blood clots, access to stroke units in hospitals and other advances in medical care (AIHW 2013).

Figure 9: Stroke death rates, by sex, 1980–2019

The line chart shows the decline in age-standardised coronary heart disease death rates between 1980 and 2019, from 108 to 24 per 100,000 population for males and from 99 to 25 for females.

Variation among population groups

Aboriginal and Torres Strait Islander people

In 2017–2019:

  • there were 276 deaths with an underlying cause of stroke among Aboriginal and Torres Strait Islander people in jurisdictions with adequate identification of Indigenous status.
  • after adjusting for differences in the age structure of the populations, the stroke death rate for Indigenous people was 1.5 times as high as that for non-Indigenous people (38 compared with 26 deaths per 100,000 population).
  • Indigenous males and females had stroke death rates 1.5 times as high as non-Indigenous males and females (Figure 10).

Socioeconomic group

In 2017–2019, the stroke death rate was 1.3 times as high for people living in the lowest socioeconomic areas compared with those living in the highest socioeconomic areas (age-standardised rates of 29 and 22 per 100,000 population).

The difference was similar for males (1.4 times as high) and females (1.3 times as high) (Figure 10).

Remoteness area

In 2017–2019, the stroke death rate in Remote and very remote areas was 1.1 times as high as in Major cities (age-standardised rates of 28 and 25 per 100,000 population).

The female rate in Remote and very remote areas was 1.1 times as high as in Major cities (28 and 24 deaths per 100,000 population), as was the male rate (26 and 24 deaths per 100,000 population) (Figure 10).

Figure 10: Stroke death rates, by population group and sex, 2017–2019

The horizontal bar chart shows that stroke death rates in 2017–2019 were higher among Indigenous Australians and people living in the lowest socioeconomic areas, but did not differ significantly by remoteness area.