Suzanne Barker-Collo

Global and regional burden of stroke during 1990–2010: findings from the Global Burden of Disease Study 2010

BACKGROUND Although stroke is the second leading cause of death worldwide, no comprehensive and comparable assessment of incidence, prevalence, mortality, disability, and epidemiological trends has been estimated for most regions. We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010) to estimate the global and regional burden of stroke during 1990-2010. METHODS We searched Medline, Embase, LILACS, Scopus, PubMed, Science Direct, Global Health Database, the WHO library, and WHO regional databases from 1990 to 2012 to identify relevant studies published between 1990 and 2010.We applied the GBD 2010 analytical technique (DisMod-MR), based on disease-specific, pre-specified associations between incidence, prevalence, and mortality, to calculate regional and country-specific estimates of stroke incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) lost by age group (<75 years, ≥ 75 years, and in total)and country income level (high-income, and low-income and middle-income) for 1990, 2005, and 2010. FINDINGS We included 119 studies (58 from high-income countries and 61 from low-income and middle-income countries). From 1990 to 2010, the age-standardised incidence of stroke significantly decreased by 12% (95% CI 6-17)in high-income countries, and increased by 12% (-3 to 22) in low-income and middle-income countries, albeit nonsignificantly. Mortality rates decreased significantly in both high income (37%, 31-41) and low-income and middle income countries (20%, 15-30). In 2010, the absolute numbers of people with fi rst stroke (16・9 million), stroke survivors (33 million), stroke-related deaths (5・9 million), and DALYs lost (102 million) were high and had significantly increased since 1990 (68%, 84%, 26%, and 12% increase, respectively), with most of the burden (68・6% incident strokes, 52・2% prevalent strokes, 70・9% stroke deaths, and 77・7% DALYs lost) in low-income and middle-income countries. In 2010, 5・2 million (31%) strokes were in children (aged <20 years old) and young and middle-aged adults(20-64 years), to which children and young and middle-aged adults from low-income and middle-income countries contributed almost 74 000 (89%) and 4・0 million (78%), respectively, of the burden. Additionally, we noted significant geographical differences of between three and ten times in stroke burden between GBD regions and countries. More than 62% of new strokes, 69・8% of prevalent strokes, 45・5% of deaths from stroke, and 71・7% of DALYs lost because of stroke were in people younger than 75 years. INTERPRETATION Although age-standardised rates of stroke mortality have decreased worldwide in the past two decades,the absolute number of people who have a stroke every year, stroke survivors, related deaths, and the overall global burden of stroke (DALYs lost) are great and increasing. Further study is needed to improve understanding of stroke determinants and burden worldwide, and to establish causes of disparities and changes in trends in stroke burden between countries of different income levels. FUNDING Bill & Melinda Gates Foundation.

Worldwide stroke incidence and early case fatality reported in 56 population-based studies: a systematic review

This systematic review of population-based studies of the incidence and early (21 days to 1 month) case fatality of stroke is based on studies published from 1970 to 2008. Stroke incidence (incident strokes only) and case fatality from 21 days to 1 month post-stroke were analysed by four decades of study, two country income groups (high-income countries and low to middle income countries, in accordance with the World Banks country classification) and, when possible, by stroke pathological type: ischaemic stroke, primary intracerebral haemorrhage, and subarachnoid haemorrhage. This Review shows a divergent, statistically significant trend in stroke incidence rates over the past four decades, with a 42% decrease in stroke incidence in high-income countries and a greater than 100% increase in stroke incidence in low to middle income countries. In 2000-08, the overall stroke incidence rates in low to middle income countries have, for the first time, exceeded the level of stroke incidence seen in high-income countries, by 20%. The time to decide whether or not stroke is an issue that should be on the governmental agenda in low to middle income countries has now passed. Now is the time for action.

Global and regional burden of first-ever ischaemic and haemorrhagic stroke during 1990–2010: findings from the Global Burden of Disease Study 2010

Summary Background The burden of ischaemic and haemorrhagic stroke varies between regions and over time. With differences in prognosis, prevalence of risk factors, and treatment strategies, knowledge of stroke pathological type is important for targeted region-specific health-care planning for stroke and could inform priorities for type-specific prevention strategies. We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010) to estimate the global and regional burden of first-ever ischaemic and haemorrhagic stroke during 1990–2010. Methods We searched Medline, Embase, LILACS, Scopus, PubMed, Science Direct, Global Health Database, the WHO library, and regional databases from 1990 to 2012 to identify relevant studies published between 1990 and 2010. We applied the GBD 2010 analytical technique (DisMod-MR) to calculate regional and country-specific estimates for ischaemic and haemorrhagic stroke incidence, mortality, mortality-to-incidence ratio, and disability-adjusted life-years (DALYs) lost, by age group (aged <75 years, ≥75 years, and in total) and country income level (high-income and low-income and middle-income) for 1990, 2005, and 2010. Findings We included 119 studies (58 from high-income countries and 61 from low-income and middle-income countries). Worldwide, the burden of ischaemic and haemorrhagic stroke increased significantly between 1990 and 2010 in terms of the absolute number of people with incident ischaemic and haemorrhagic stroke (37% and 47% increase, respectively), number of deaths (21% and 20% increase), and DALYs lost (18% and 14% increase). In the past two decades in high-income countries, incidence of ischaemic stroke reduced significantly by 13% (95% CI 6–18), mortality by 37% (19–39), DALYs lost by 34% (16–36), and mortality-to-incidence ratios by 21% (10–27). For haemorrhagic stroke, incidence reduced significantly by 19% (1–15), mortality by 38% (32–43), DALYs lost by 39% (32–44), and mortality-to-incidence ratios by 27% (19–35). By contrast, in low-income and middle-income countries, we noted a significant increase of 22% (5–30) in incidence of haemorrhagic stroke and a 6% (–7 to 18) non-significant increase in the incidence of ischaemic stroke. Mortality rates for ischaemic stroke fell by 14% (9–19), DALYs lost by 17% (–11 to 21%), and mortality-to-incidence ratios by 16% (–12 to 22). For haemorrhagic stroke in low-income and middle-income countries, mortality rates reduced by 23% (–18 to 25%), DALYs lost by 25% (–21 to 28), and mortality-to-incidence ratios by 36% (–34 to 28). Interpretation Although age-standardised mortality rates for ischaemic and haemorrhagic stroke have decreased in the past two decades, the absolute number of people who have these stroke types annually, and the number with related deaths and DALYs lost, is increasing, with most of the burden in low-income and middle-income countries. Further study is needed in these countries to identify which subgroups of the population are at greatest risk and who could be targeted for preventive efforts.

Incidence of traumatic brain injury in New Zealand: a population-based study

BACKGROUND Traumatic brain injury (TBI) is the leading cause of long-term disability in children and young adults worldwide. However, accurate information about its incidence does not exist. We aimed to estimate the burden of TBI in rural and urban populations in New Zealand across all ages and TBI severities. METHODS We did a population-based incidence study in an urban (Hamilton) and rural (Waikato District) population in New Zealand. We registered all cases of TBI (admitted to hospital or not, fatal or non-fatal) that occurred in the population between March 1, 2010, and Feb 28, 2011, using multiple overlapping sources of information. We calculated incidence per 100,000 person-years with 95% CIs using a Poisson distribution. We calculated rate ratios [RRs] to compare the age-standardised rates between sex, ethnicity, and residency (urban, rural) groups. We used direct standardisation to age-standardise the rates to the world population. RESULTS The total incidence of TBI per 100,000 person-years was 790 cases (95% CI 749-832); incidence per 100,000 person-years of mild TBI was 749 cases (709-790) and of moderate to severe TBI was 41 cases (31-51). Children (aged 0-14 years) and adolescents and young adults (aged 15-34 years) constituted almost 70% of all TBI cases. TBI affected boys and men more than women and girls (RR 1·77, 95% CI 1·58-1·97). Most TBI cases were due to falls (38% [516 of 1369]), mechanical forces (21% [288 of 1369]), transport accidents (20% [277 of 1369]), and assaults (17% [228 of 1369]). Compared with people of European origin, Maori people had a greater risk of mild TBI (RR 1·23, 95% CI 1·08-1·39). Incidence of moderate to severe TBI in the rural population (73 per 100,000 person-years [95% CI 50-107) was almost 2·5 times greater than in the urban population (31 per 100 000 person-years [23-42]). INTERPRETATION Our findings suggest that the incidence of TBI, especially mild TBI, in New Zealand is far greater than would be estimated from the findings of previous studies done in other high-income countries. Our age-specific and residency-specific data for TBI incidence overall and by mechanism of injury should be considered when planning prevention and TBI care services. FUNDING Health Research Council of New Zealand.

Update on the Global Burden of Ischemic and Hemorrhagic Stroke in 1990-2013: The GBD 2013 Study

Background: Global stroke epidemiology is changing rapidly. Although age-standardized rates of stroke mortality have decreased worldwide in the past 2 decades, the absolute numbers of people who have a stroke every year, and live with the consequences of stroke or die from their stroke, are increasing. Regular updates on the current level of stroke burden are important for advancing our knowledge on stroke epidemiology and facilitate organization and planning of evidence-based stroke care. Objectives: This study aims to estimate incidence, prevalence, mortality, disability-adjusted life years (DALYs) and years lived with disability (YLDs) and their trends for ischemic stroke (IS) and hemorrhagic stroke (HS) for 188 countries from 1990 to 2013. Methodology: Stroke incidence, prevalence, mortality, DALYs and YLDs were estimated using all available data on mortality and stroke incidence, prevalence and excess mortality. Statistical models and country-level covariate data were employed, and all rates were age-standardized to a global population. All estimates were produced with 95% uncertainty intervals (UIs). Results: In 2013, there were globally almost 25.7 million stroke survivors (71% with IS), 6.5 million deaths from stroke (51% died from IS), 113 million DALYs due to stroke (58% due to IS) and 10.3 million new strokes (67% IS). Over the 1990-2013 period, there was a significant increase in the absolute number of DALYs due to IS, and of deaths from IS and HS, survivors and incident events for both IS and HS. The preponderance of the burden of stroke continued to reside in developing countries, comprising 75.2% of deaths from stroke and 81.0% of stroke-related DALYs. Globally, the proportional contribution of stroke-related DALYs and deaths due to stroke compared to all diseases increased from 1990 (3.54% (95% UI 3.11-4.00) and 9.66% (95% UI 8.47-10.70), respectively) to 2013 (4.62% (95% UI 4.01-5.30) and 11.75% (95% UI 10.45-13.31), respectively), but there was a diverging trend in developed and developing countries with a significant increase in DALYs and deaths in developing countries, and no measurable change in the proportional contribution of DALYs and deaths from stroke in developed countries. Conclusion: Global stroke burden continues to increase globally. More efficient stroke prevention and management strategies are urgently needed to halt and eventually reverse the stroke pandemic, while universal access to organized stroke services should be a priority.

Auckland Stroke Outcomes Study Part 2: Cognition and functional outcomes 5 years poststroke

Background: Understanding the extent of long-term neuropsychological deficits poststroke and their contribution to functional outcomes is essential for evidence-based rehabilitation and resource planning, and could improve stroke outcomes. However, most existing neuropsychological stroke data are not population-based, examine limited outcomes, and have short-term follow-up. Methods: This population-based long-term stroke follow-up study examined associations between neuropsychological deficits (memory, executive function, information processing speed [IPS], visuoperceptual/construction ability, language), depression, and a range of functional outcomes and their interrelationships 5 years poststroke. Results: The greatest proportion of the 307 participants exhibited neuropsychological functioning within the average range, and about 30%–50% performed at lower levels on most measures; few performed above the average range. Deficits were most common in executive functioning and IPS, and 30.4% of participants were depressed. While correlation analyses indicate all cognitive domains are significantly related to functional outcomes, multiple regression analyses showed that only IPS and visuoperceptual ability made significant independent contributions to functional outcomes over and above age, depression, and current Barthel Index. Depression also made a significant and independent contribution to functional outcomes. Conclusion: A considerable proportion of 5-year stroke survivors experience neuropsychological deficits, with these being more likely to involve IPS and executive functioning. Visuoperceptual/construction abilities, visual memory, and IPS were independently associated with handicap, disability, and health-related quality of life over and above contributions made by age, depression, and stroke severity, suggesting these areas are important targets for rehabilitation to improve overall stroke recovery and should be evaluated in future randomized controlled trials.

Reducing Attention Deficits After Stroke Using Attention Process Training A Randomized Controlled Trial

Background and Purpose— Impaired attention contributes to poor stroke outcomes. Attention process training (APT) reduces attention deficits after traumatic brain injury. There was no evidence for effectiveness of APT in stroke patients. This trial evaluated effectiveness of APT in improving attention and broader outcomes in stroke survivors 6 months after stroke. Methods— Participants in this prospective, single-blinded, randomized, clinical trial were 78 incident stroke survivors admitted over 18 months and identified via neuropsychological assessment as having attention deficit. Participants were randomly allocated to standard care plus up to 30 hours of APT or standard care alone. Both groups were impaired (z≤−2.0) across measures of attention at baseline, with the exception of Paced Auditory Serial Addition Test, which was below average (z≤−1.0). Outcome assessment occurred at 5 weeks and 6 months after randomization. The primary outcome was Integrated Visual Auditory Continuous Performance Test Full-Scale Attention Quotient. Results— APT resulted in a significantly greater (P<0.01) improvement on the primary outcome than standard care. Difference in change on the Cognitive Failures Questionnaire approached significance (P=0.07). Differences on other measures of attention and broader outcomes were not significant. Conclusion— APT is a viable and effective means of improving attention deficits after incident stroke.

Auckland Stroke Outcomes Study: Part 1: Gender, stroke types, ethnicity, and functional outcomes 5 years poststroke

Background: Studying long-term stroke outcomes including body functioning (neurologic and neuropsychological impairments) and activity limitations and participation is essential for long-term evidence-based rehabilitation and service planning, resource allocation, and improving health outcomes in stroke. However, reliable data to address these issues is lacking. Methods: This study (February 2007–December 2008) sourced its participants from the population-based incidence study conducted in Auckland in 2002–2003. Participants completed structured self-administered questionnaires, and a face-to-face interview including a battery of neuropsychological tests. Logistic regression analysis was used to analyze associations between and within functional outcomes and their potential predictors. Results: Of 418 5-year stroke survivors, two-thirds had good functional outcome in terms of neurologic impairment and disability (defined as modified Rankin Score <3), 22.5% had cognitive impairment indicative of dementia, 20% had experienced a recurrent stroke, almost 15% were institutionalized, and 29.6% had symptoms suggesting depression. Highly significant correlations were found between and within various measurements of body functioning (especially neuropsychological impairments), activity, and participation. Age, dependency, and depression were independently associated with most outcomes analyzed. Conclusions: The strong associations between neuropsychological impairment and other functional outcomes and across various measurements of body functioning, activity, and participation justify utilizing a multidisciplinary approach to studying and managing long-term stroke outcomes. Observed gender and ethnic differences in some important stroke outcomes warrant further investigations.

The Impact of Neuropsychological Deficits on Functional Stroke Outcomes

This review examines the available literature on neuropsychological outcomes of stroke and the literature on the ability of specific areas of neuropsychological deficit to predict functional stroke outcome. The literature reviewed indicates that post-stroke deficits in executive function, memory, language, and speed of processing are common, with those identified as having progressive ‘post-stroke dementia’ presenting with a similar, though more impaired profile, with increased impairments particularly noted in the area of memory. It is clear that some aspects of neuropsychological functioning (e.g., presence of neglect, aphasia, anosognosia; and verbal memory and attention deficits) show promise as a means of predicting post-stroke functional outcomes. Examining the available literature, it becomes evident that there is a need for long-term, large scale (i.e., population based) follow-up studies, evaluating likely long-term neuropsychological outcomes of stroke and their prognostic utility.

Stroke Prevalence, Mortality and Disability-Adjusted Life Years in Adults Aged 20-64 Years in 1990-2013: Data from the Global Burden of Disease 2013 Study

Background: Recent evidence suggests that stroke is increasing as a cause of morbidity and mortality in younger adults, where it carries particular significance for working individuals. Accurate and up-to-date estimates of stroke burden are important for planning stroke prevention and management in younger adults. Objectives: This study aims to estimate prevalence, mortality and disability-adjusted life years (DALYs) and their trends for total, ischemic stroke (IS) and hemorrhagic stroke (HS) in the world for 1990-2013 in adults aged 20-64 years. Methodology: Stroke prevalence, mortality and DALYs were estimated using the Global Burden of Disease (GBD) 2013 methods. All available data on rates of stroke incidence, excess mortality, prevalence and death were collected. Statistical models were used along with country-level covariates to estimate country-specific stroke burden. Stroke-specific disability weights were used to compute years lived with disability and DALYs. Means and 95% uncertainty intervals (UIs) were calculated for prevalence, mortality and DALYs. The median of the percent change and 95% UI were determined for the period from 1990 to 2013. Results: In 2013, in younger adults aged 20-64 years, the global prevalence of HS was 3,725,085 cases (95% UI 3,548,098-3,871,018) and IS was 7,258,216 cases (95% UI 6,996,272-7,569,403). Globally, between 1990 and 2013, there were significant increases in absolute numbers and prevalence rates of both HS and IS for younger adults. There were 1,483,707 (95% UI 1,340,579-1,658,929) stroke deaths globally among younger adults but the number of deaths from HS (1,047,735 (95% UI 945,087-1,184,192)) was significantly higher than the number of deaths from IS (435,972 (95% UI 354,018-504,656)). There was a 20.1% (95% UI -23.6 to -10.3) decline in the number of total stroke deaths among younger adults in developed countries but a 36.7% (95% UI 26.3-48.5) increase in developing countries. Death rates for all strokes among younger adults declined significantly in developing countries from 47 (95% UI 42.6-51.7) in 1990 to 39 (95% UI 35.0-43.8) in 2013. Death rates for all strokes among younger adults also declined significantly in developed countries from 33.3 (95% UI 29.8-37.0) in 1990 to 23.5 (95% UI 21.1-26.9) in 2013. A significant decrease in HS death rates for younger adults was seen only in developed countries between 1990 and 2013 (19.8 (95% UI 16.9-22.6) and 13.7 (95% UI 12.1-15.9)) per 100,000). No significant change was detected in IS death rates among younger adults. The total DALYs from all strokes in those aged 20-64 years was 51,429,440 (95% UI 46,561,382-57,320,085). Globally, there was a 24.4% (95% UI 16.6-33.8) increase in total DALY numbers for this age group, with a 20% (95% UI 11.7-31.1) and 37.3% (95% UI 23.4-52.2) increase in HS and IS numbers, respectively. Conclusions: Between 1990 and 2013, there were significant increases in prevalent cases, total deaths and DALYs due to HS and IS in younger adults aged 20-64 years. Death and DALY rates declined in both developed and developing countries but a significant increase in absolute numbers of stroke deaths among younger adults was detected in developing countries. Most of the burden of stroke was in developing countries. In 2013, the greatest burden of stroke among younger adults was due to HS. While the trends in declining death and DALY rates in developing countries are encouraging, these regions still fall far behind those of developed regions of the world. A more aggressive approach toward primary prevention and increased access to adequate healthcare services for stroke is required to substantially narrow these disparities.