Laurie Anderson

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.

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.

Complex interventions and their implications for systematic reviews: A pragmatic approach

Complex interventions present unique challenges for systematic reviews. Current debates tend to center around describing complexity, rather than providing guidance on what to do about it. At a series of meetings during 2009-2012, we met to review the challenges and practical steps reviewer could take to incorporate a complexity perspective into systematic reviews. Based on this, we outline a pragmatic approach to dealing with complexity, beginning, as for any review, with clearly defining the research question(s). We argue that reviews of complex interventions can themselves be simple or complex, depending on the question to be answered. In systematic reviews and evaluations of complex interventions, it will be helpful to start by identifying the sources of complexity, then mapping aspects of complexity in the intervention onto the appropriate sources of evidence (such as specific types of quantitative or qualitative study). Although we focus on systematic reviews, the general approach is also applicable to primary research that is aimed at evaluating complex interventions. Although the examples are drawn from health care, the approach may also be applied to other sectors (e.g., social policy or international development). We end by concluding that systematic reviews should follow the principle of Occams razor: explanations should be as complex as they need to be and no more.

The epidemiology of stroke in the Middle East and North Africa

Stroke is the second leading cause of death in the world. In the Middle East and North Africa stroke is increasingly becoming a major health problem, with projections that deaths from it will nearly double by 2030. This systematic review aims to bring together age-adjusted epidemiological data of stroke in this region. A literature review of five databases was conducted. Twenty-three papers met the criteria. The incidence of stroke varied extensively among studies. Studies reported rates from 29.8 per 100000 people in Saudi Arabia to 57 per 100000 people in Bahrain. Furthermore, the 28-day case mortality rate also differed among studies, ranging from 10% in Kuwait to 31.5% in Iran. The rates are comparable with those in the Western world; however, the population of the region is younger. The Middle East and North Africa are lacking in data on the epidemiology of stroke. There is an urgent need to develop strategies to prevent and better care for stroke patients in the Middle East and North Africa.

Investigating complexity in systematic reviews of interventions by using a spectrum of methods

Systematic reviews framed by PICOS (Populations, Interventions, Comparisons, Outcomes, and Study designs) have been valuable for synthesizing evidence about the effects of interventions. However, this framework is limited in its utility for exploring the influence of variations within populations or interventions, or about the mechanisms of action or causal pathways thought to mediate outcomes, other contextual factors that might similarly moderate outcomes, or how and when these mechanisms and elements interact. Valuable insights into these issues come from configurative as well as aggregative methods of synthesis. This article considers the range of evidence that can be used in systematic reviews of interventions to investigate complexity in terms of potential sources of variation in interventions and their effects, and presents a continuum of purposes for, and approaches to, evidence synthesis. Choosing an appropriate synthesis method takes into account whether the purpose of the synthesis is to generate, explore, or test theories. Taking complexity into account in a synthesis of economic evidence similarly shifts emphasis from evidence synthesis strategies focused on aggregation toward configurative strategies that aim to develop, explore, and refine (in advance of testing) theories or explanations of how and why interventions are more or less resource intensive, costly or cost-effective in different settings, or when implemented in different ways.

Knowledge translation strategies to improve the use of evidence in public health decision making in local government: intervention design and implementation plan

BackgroundKnowledge translation strategies are an approach to increase the use of evidence within policy and practice decision-making contexts. In clinical and health service contexts, knowledge translation strategies have focused on individual behavior change, however the multi-system context of public health requires a multi-level, multi-strategy approach. This paper describes the design of and implementation plan for a knowledge translation intervention for public health decision making in local government.MethodsFour preliminary research studies contributed findings to the design of the intervention: a systematic review of knowledge translation intervention effectiveness research, a scoping study of knowledge translation perspectives and relevant theory literature, a survey of the local government public health workforce, and a study of the use of evidence-informed decision-making for public health in local government. A logic model was then developed to represent the putative pathways between intervention inputs, processes, and outcomes operating between individual-, organizational-, and system-level strategies. This formed the basis of the intervention plan.ResultsThe systematic and scoping reviews identified that effective and promising strategies to increase access to research evidence require an integrated intervention of skill development, access to a knowledge broker, resources and tools for evidence-informed decision making, and networking for information sharing. Interviews and survey analysis suggested that the intervention needs to operate at individual and organizational levels, comprising workforce development, access to evidence, and regular contact with a knowledge broker to increase access to intervention evidence; develop skills in appraisal and integration of evidence; strengthen networks; and explore organizational factors to build organizational cultures receptive to embedding evidence in practice. The logic model incorporated these inputs and strategies with a set of outcomes to measure the intervention’s effectiveness based on the theoretical frameworks, evaluation studies, and decision-maker experiences.ConclusionDocumenting the design of and implementation plan for this knowledge translation intervention provides a transparent, theoretical, and practical approach to a complex intervention. It provides significant insights into how practitioners might engage with evidence in public health decision making. While this intervention model was designed for the local government context, it is likely to be applicable and generalizable across sectors and settings.Trial registrationAustralia New Zealand Clinical Trials Register ACTRN12609000953235.

An exploratory cluster randomised controlled trial of knowledge translation strategies to support evidence-informed decision-making in local governments (The KT4LG study)

BackgroundChildhood overweight and obesity is the most prevalent and, arguably, politically complex child health problem internationally. Governments, communities and industry have important roles to play, and are increasingly expected to deliver an evidence-informed system-wide prevention program. However, efforts are impeded by a lack of organisational access to and use of research evidence. This study aims to identify feasible, acceptable and ideally, effective knowledge translation (KT) strategies to increase evidence-informed decision-making in local governments, within the context of childhood obesity prevention as a national policy priority.Methods/DesignThis paper describes the methods for KT4LG, a cluster randomised controlled trial which is exploratory in nature, given the limited evidence base and methodological advances. KT4LG aims to examine a program of KT strategies to increase the use of research evidence in informing public health decisions in local governments. KT4LG will also assess the feasibility and acceptability of the intervention. The intervention program comprises a facilitated program of evidence awareness, access to tailored research evidence, critical appraisal skills development, networking and evidence summaries and will be compared to provision of evidence summaries alone in the control program. 28 local governments were randomised to intervention or control, using computer generated numbers, stratified by budget tertile (high, medium or low). Questionnaires will be used to measure impact, costs, and outcomes, and key informant interviews will be used to examine processes, feasibility, and experiences. Policy tracer studies will be included to examine impact of intervention on policies within relevant government policy documents.DiscussionKnowledge translation intervention studies with a focus on public health and prevention are very few in number. Thus, this study will provide essential data on the experience of program implementation and evaluation of a system-integrated intervention program employed within the local government public health context. Standardised programs of system, organisational and individual KT strategies have not been described or rigorously evaluated. As such, the findings will make a significant contribution to understanding whether a facilitated program of KT strategies hold promise for facilitating evidence-informed public health decision making within complex multisectoral government organisations.Trial registrationAustralia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12609000953235

Issues relating to selective reporting when including non‐randomized studies in systematic reviews on the effects of healthcare interventions

BACKGROUND Selective outcome and analysis reporting (SOR and SAR) occur when only a subset of outcomes measured and analyzed in a study is fully reported, and are an important source of potential bias. KEY METHODOLOGICAL ISSUES We describe what is known about the prevalence and effects of SOR and SAR in both randomized controlled trials (RCTs) and non-randomized studies (NRS), and the effects of SOR and SAR on summary effect estimates and conclusions in systematic reviews of the effectiveness of healthcare interventions. GUIDANCE Review authors should always suspect SOR and SAR in reviews that include NRS, assess primary studies for the risk of bias, and make reasonable attempts to retrieve study protocols or other documentation developed before study recruitment began. There are clues that may suggest SOR or SAR in NRS, including differences between the methods and results sections of the publication, study funder, and differences between study protocol or registration information and the study report. CONCLUSION Existing evidence about reporting biases in primary studies comes almost exclusively from methodological reviews of RCTs. The prevalence and impact of SOR and SAR in NRS are likely even greater than in RCTs but it is difficult to identify and confirm selective reporting in NRS. Copyright

Stroke in South Asia: A Systematic Review of Epidemiologic Literature from 1980 to 2010

Background: Globally 15 million people have an acute stroke every year and one third of them die secondary to stroke events. Most research on stroke prevention and treatment is done in developed countries, yet more than 85% of strokes occur in developing countries. In particular, stroke remains an underrecognized cause of death and disability in South Asia. Methods: We conducted a systematic review to identify reliable and comparable epidemiological evidence on stroke in South Asia from 1980 to 2010. Publications were screened for eligibility to identify only population-based stroke studies. Results: Of the 71 studies retrieved, only 6 studies from South Asia gave us acceptable estimates of the burden of stroke. Population-based studies from South Asia have stroke prevalence in the range of 45–471 per 100,000. The age-adjusted incidence rate varied from approximately 145 per 100,000 to 262 per 100,000. Rural parts of South Asia have a lower stroke prevalence compared with urban areas. Conclusions: Our review highlights the paucity of research data in South Asia. This must be addressed in order to accurately determine the burden of stroke in South Asia, so that specific policy recommendations can be formulated to combat the stroke epidemic in this region.

Strengthening evaluation to capture the breadth of public health practice: ideal vs. real.

Tahna L. Pettman2, Rebecca Armstrong1,2, Jodie Doyle1,2, Belinda Burford1,2, Laurie M. Anderson2, Tessa Hillgrove3, Nikki Honey3, Elizabeth Waters1,2 Jack Brockhoff Child Health and Wellbeing Program, McCaughey Centre, Melbourne School of Population Health, University of Melbourne, Melbourne, Australia Cochrane Public Health Group, McCaughey Centre, Melbourne School of Population Health, University of Melbourne, Melbourne, Australia Knowledge and Environments for Health Unit, The Victorian Health Promotion Foundation (VicHealth), Carlton, Victoria, Australia Address correspondence to Tahna Pettman, E-mail: tpettman@unimelb.edu.au