Assessing the complexity of interventions within systematic reviews: development, content and use of a new tool (iCAT_SR).

BACKGROUND: Health interventions fall along a spectrum from simple to more complex. There is wide interest in methods for reviewing 'complex interventions', but few transparent approaches for assessing intervention complexity in systematic reviews. Such assessments may assist review authors in, for example, systematically describing interventions and developing logic models. This paper describes the development and application of the intervention Complexity Assessment Tool for Systematic Reviews (iCAT_SR), a new tool to assess and categorise levels of intervention complexity in systematic reviews. METHODS: We developed the iCAT_SR by adapting and extending an existing complexity assessment tool for randomized trials. We undertook this adaptation using a consensus approach in which possible complexity dimensions were circulated for feedback to a panel of methodologists with expertise in complex interventions and systematic reviews. Based on these inputs, we developed a draft version of the tool. We then invited a second round of feedback from the panel and a wider group of systematic reviewers. This informed further refinement of the tool. RESULTS: The tool comprises ten dimensions: (1) the number of active components in the intervention; (2) the number of behaviours of recipients to which the intervention is directed; (3) the range and number of organizational levels targeted by the intervention; (4) the degree of tailoring intended or flexibility permitted across sites or individuals in applying or implementing the intervention; (5) the level of skill required by those delivering the intervention; (6) the level of skill required by those receiving the intervention; (7) the degree of interaction between intervention components; (8) the degree to which the effects of the intervention are context dependent; (9) the degree to which the effects of the interventions are changed by recipient or provider factors; (10) and the nature of the causal pathway between intervention and outcome. Dimensions 1-6 are considered 'core' dimensions. Dimensions 7-10 are optional and may not be useful for all interventions. CONCLUSIONS: The iCAT_SR tool facilitates more in-depth, systematic assessment of the complexity of interventions in systematic reviews and can assist in undertaking reviews and interpreting review findings. Further testing of the tool is now needed.

Community coalition-driven interventions to reduce health disparities among racial and ethnic minority populations.

BACKGROUND: Racial and ethnic disparities in health status are pervasive at all stages of the life cycle. One approach to reducing health disparities involves mobilizing community coalitions that include representatives of target populations to plan and implement interventions for community level change. A systematic examination of coalition-led interventions is needed to inform decision making about the use of community coalition models. OBJECTIVES: To assess effects of community coalition-driven interventions in improving health status or reducing health disparities among racial and ethnic minority populations. SEARCH METHODS: We searched MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, Social Science Citation Index, Dissertation Abstracts, System for Information on Grey Literature in Europe (SIGLE) (from January 1990 through September 30, 2013), and Global Health Library (from January 1990 through March 31, 2014). SELECTION CRITERIA: Cluster-randomized controlled trials, randomized controlled trials, quasi-experimental designs, controlled before-after studies, interrupted time series studies, and prospective controlled cohort studies. Only studies of community coalitions with at least one racial or ethnic minority group representing the target population and at least two community public or private organizations are included. Major outcomes of interest are direct measures of health status, as well as lifestyle factors when evidence indicates that these have an effect on the direct measures performed. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed risk of bias for each study. MAIN RESULTS: Fifty-eight community coalition-driven intervention studies were included. No study was considered to be at low risk of bias. Behavioral change outcomes and health status change outcomes were analyzed separately. Outcomes are grouped by intervention type. Pooled effects across intervention types are not presented because the diverse community coalition-led intervention studies did not examine the same constructs or relationships, and they used dissimilar methodological designs. Broad-scale community system level change strategies led to little or no difference in measures of health behavior or health status (very low-certainty evidence). Broad health and social care system level strategies leds to small beneficial changes in measures of health behavior or health status in large samples of community residents (very low-certainty evidence). Lay community health outreach worker interventions led to beneficial changes in health behavior measures of moderate magnitude in large samples of community residents (very low-certainty evidence). Lay community health outreach worker interventions may lead to beneficial changes in health status measures in large samples of community residents; however, results were not consistent across studies (low-certainty evidence). Group-based health education led by professional staff resulted in moderate improvement in measures of health behavior (very low-certainty evidence) or health status (low-certainty evidence). Adverse outcomes of community coalition-led interventions were not reported. AUTHORS' CONCLUSIONS: Coalition-led interventions are characterized by connection of multi-sectoral networks of health and human service providers with ethnic and racial minority communities. These interventions benefit a diverse range of individual health outcomes and behaviors, as well as health and social care delivery systems. Evidence in this review shows that interventions led by community coalitions may connect health and human service providers with ethnic and racial minority communities in ways that benefit individual health outcomes and behaviors, as well as care delivery systems. However, because information on characteristics of the coalitions themselves is insufficient, evidence does not provide an explanation for the underlying mechanisms of beneficial effects. Thus, a definitive answer as to whether a coalition-led intervention adds extra value to the types of community engagement intervention strategies described in this review remains unattainable.

Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Reliable and timely information on the leading causes of death in populations, and how these are changing, is a crucial input into health policy debates. In the Global Burden of Diseases, Injuries, and Risk Factors Study 2010 (GBD 2010), we aimed to estimate annual deaths for the world and 21 regions between 1980 and 2010 for 235 causes, with uncertainty intervals (UIs), separately by age and sex. METHODS: We attempted to identify all available data on causes of death for 187 countries from 1980 to 2010 from vital registration, verbal autopsy, mortality surveillance, censuses, surveys, hospitals, police records, and mortuaries. We assessed data quality for completeness, diagnostic accuracy, missing data, stochastic variations, and probable causes of death. We applied six different modelling strategies to estimate cause-specific mortality trends depending on the strength of the data. For 133 causes and three special aggregates we used the Cause of Death Ensemble model (CODEm) approach, which uses four families of statistical models testing a large set of different models using different permutations of covariates. Model ensembles were developed from these component models. We assessed model performance with rigorous out-of-sample testing of prediction error and the validity of 95% UIs. For 13 causes with low observed numbers of deaths, we developed negative binomial models with plausible covariates. For 27 causes for which death is rare, we modelled the higher level cause in the cause hierarchy of the GBD 2010 and then allocated deaths across component causes proportionately, estimated from all available data in the database. For selected causes (African trypanosomiasis, congenital syphilis, whooping cough, measles, typhoid and parathyroid, leishmaniasis, acute hepatitis E, and HIV/AIDS), we used natural history models based on information on incidence, prevalence, and case-fatality. We separately estimated cause fractions by aetiology for diarrhoea, lower respiratory infections, and meningitis, as well as disaggregations by subcause for chronic kidney disease, maternal disorders, cirrhosis, and liver cancer. For deaths due to collective violence and natural disasters, we used mortality shock regressions. For every cause, we estimated 95% UIs that captured both parameter estimation uncertainty and uncertainty due to model specification where CODEm was used. We constrained cause-specific fractions within every age-sex group to sum to total mortality based on draws from the uncertainty distributions. FINDINGS: In 2010, there were 52·8 million deaths globally. At the most aggregate level, communicable, maternal, neonatal, and nutritional causes were 24·9% of deaths worldwide in 2010, down from 15·9 million (34·1%) of 46·5 million in 1990. This decrease was largely due to decreases in mortality from diarrhoeal disease (from 2·5 to 1·4 million), lower respiratory infections (from 3·4 to 2·8 million), neonatal disorders (from 3·1 to 2·2 million), measles (from 0·63 to 0·13 million), and tetanus (from 0·27 to 0·06 million). Deaths from HIV/AIDS increased from 0·30 million in 1990 to 1·5 million in 2010, reaching a peak of 1·7 million in 2006. Malaria mortality also rose by an estimated 19·9% since 1990 to 1·17 million deaths in 2010. Tuberculosis killed 1·2 million people in 2010. Deaths from non-communicable diseases rose by just under 8 million between 1990 and 2010, accounting for two of every three deaths (34·5 million) worldwide by 2010. 8 million people died from cancer in 2010, 38% more than two decades ago; of these, 1·5 million (19%) were from trachea, bronchus, and lung cancer. Ischaemic heart disease and stroke collectively killed 12·9 million people in 2010, or one in four deaths worldwide, compared with one in five in 1990; 1·3 million deaths were due to diabetes, twice as many as in 1990. The fraction of global deaths due to injuries (5·1 million deaths) was marginally higher in 2010 (9·6%) compared with two decades earlier (8·8%). This was driven by a 46% rise in deaths worldwide due to road traffic accidents (1·3 million in 2010) and a rise in deaths from falls. Ischaemic heart disease, stroke, chronic obstructive pulmonary disease (COPD), lower respiratory infections, lung cancer, and HIV/AIDS were the leading causes of death in 2010. Ischaemic heart disease, lower respiratory infections, stroke, diarrhoeal disease, malaria, and HIV/AIDS were the leading causes of years of life lost due to premature mortality (YLLs) in 2010, similar to what was estimated for 1990, except for HIV/AIDS and preterm birth complications. YLLs from lower respiratory infections and diarrhoea decreased by 45-54% since 1990; ischaemic heart disease and stroke YLLs increased by 17-28%. Regional variations in leading causes of death were substantial. Communicable, maternal, neonatal, and nutritional causes still accounted for 76% of premature mortality in sub-Saharan Africa in 2010. Age standardised death rates from some key disorders rose (HIV/AIDS, Alzheimer's disease, diabetes mellitus, and chronic kidney disease in particular), but for most diseases, death rates fell in the past two decades; including major vascular diseases, COPD, most forms of cancer, liver cirrhosis, and maternal disorders. For other conditions, notably malaria, prostate cancer, and injuries, little change was noted. INTERPRETATION: Population growth, increased average age of the world's population, and largely decreasing age-specific, sex-specific, and cause-specific death rates combine to drive a broad shift from communicable, maternal, neonatal, and nutritional causes towards non-communicable diseases. Nevertheless, communicable, maternal, neonatal, and nutritional causes remain the dominant causes of YLLs in sub-Saharan Africa. Overlaid on this general pattern of the epidemiological transition, marked regional variation exists in many causes, such as interpersonal violence, suicide, liver cancer, diabetes, cirrhosis, Chagas disease, African trypanosomiasis, melanoma, and others. Regional heterogeneity highlights the importance of sound epidemiological assessments of the causes of death on a regular basis. FUNDING: Bill & Melinda Gates Foundation.

Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Non-fatal health outcomes from diseases and injuries are a crucial consideration in the promotion and monitoring of individual and population health. The Global Burden of Disease (GBD) studies done in 1990 and 2000 have been the only studies to quantify non-fatal health outcomes across an exhaustive set of disorders at the global and regional level. Neither effort quantified uncertainty in prevalence or years lived with disability (YLDs). METHODS: Of the 291 diseases and injuries in the GBD cause list, 289 cause disability. For 1160 sequelae of the 289 diseases and injuries, we undertook a systematic analysis of prevalence, incidence, remission, duration, and excess mortality. Sources included published studies, case notification, population-based cancer registries, other disease registries, antenatal clinic serosurveillance, hospital discharge data, ambulatory care data, household surveys, other surveys, and cohort studies. For most sequelae, we used a Bayesian meta-regression method, DisMod-MR, designed to address key limitations in descriptive epidemiological data, including missing data, inconsistency, and large methodological variation between data sources. For some disorders, we used natural history models, geospatial models, back-calculation models (models calculating incidence from population mortality rates and case fatality), or registration completeness models (models adjusting for incomplete registration with health-system access and other covariates). Disability weights for 220 unique health states were used to capture the severity of health loss. YLDs by cause at age, sex, country, and year levels were adjusted for comorbidity with simulation methods. We included uncertainty estimates at all stages of the analysis. FINDINGS: Global prevalence for all ages combined in 2010 across the 1160 sequelae ranged from fewer than one case per 1 million people to 350,000 cases per 1 million people. Prevalence and severity of health loss were weakly correlated (correlation coefficient -0·37). In 2010, there were 777 million YLDs from all causes, up from 583 million in 1990. The main contributors to global YLDs were mental and behavioural disorders, musculoskeletal disorders, and diabetes or endocrine diseases. The leading specific causes of YLDs were much the same in 2010 as they were in 1990: low back pain, major depressive disorder, iron-deficiency anaemia, neck pain, chronic obstructive pulmonary disease, anxiety disorders, migraine, diabetes, and falls. Age-specific prevalence of YLDs increased with age in all regions and has decreased slightly from 1990 to 2010. Regional patterns of the leading causes of YLDs were more similar compared with years of life lost due to premature mortality. Neglected tropical diseases, HIV/AIDS, tuberculosis, malaria, and anaemia were important causes of YLDs in sub-Saharan Africa. INTERPRETATION: Rates of YLDs per 100,000 people have remained largely constant over time but rise steadily with age. Population growth and ageing have increased YLD numbers and crude rates over the past two decades. Prevalences of the most common causes of YLDs, such as mental and behavioural disorders and musculoskeletal disorders, have not decreased. Health systems will need to address the needs of the rising numbers of individuals with a range of disorders that largely cause disability but not mortality. Quantification of the burden of non-fatal health outcomes will be crucial to understand how well health systems are responding to these challenges. Effective and affordable strategies to deal with this rising burden are an urgent priority for health systems in most parts of the world. FUNDING: Bill & Melinda Gates Foundation.

Disability-adjusted life years (DALYs) for 291 diseases and injuries in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010.

BACKGROUND: Measuring disease and injury burden in populations requires a composite metric that captures both premature mortality and the prevalence and severity of ill-health. The 1990 Global Burden of Disease study proposed disability-adjusted life years (DALYs) to measure disease burden. No comprehensive update of disease burden worldwide incorporating a systematic reassessment of disease and injury-specific epidemiology has been done since the 1990 study. We aimed to calculate disease burden worldwide and for 21 regions for 1990, 2005, and 2010 with methods to enable meaningful comparisons over time. METHODS: We calculated DALYs as the sum of years of life lost (YLLs) and years lived with disability (YLDs). DALYs were calculated for 291 causes, 20 age groups, both sexes, and for 187 countries, and aggregated to regional and global estimates of disease burden for three points in time with strictly comparable definitions and methods. YLLs were calculated from age-sex-country-time-specific estimates of mortality by cause, with death by standardised lost life expectancy at each age. YLDs were calculated as prevalence of 1160 disabling sequelae, by age, sex, and cause, and weighted by new disability weights for each health state. Neither YLLs nor YLDs were age-weighted or discounted. Uncertainty around cause-specific DALYs was calculated incorporating uncertainty in levels of all-cause mortality, cause-specific mortality, prevalence, and disability weights. FINDINGS: Global DALYs remained stable from 1990 (2·503 billion) to 2010 (2·490 billion). Crude DALYs per 1000 decreased by 23% (472 per 1000 to 361 per 1000). An important shift has occurred in DALY composition with the contribution of deaths and disability among children (younger than 5 years of age) declining from 41% of global DALYs in 1990 to 25% in 2010. YLLs typically account for about half of disease burden in more developed regions (high-income Asia Pacific, western Europe, high-income North America, and Australasia), rising to over 80% of DALYs in sub-Saharan Africa. In 1990, 47% of DALYs worldwide were from communicable, maternal, neonatal, and nutritional disorders, 43% from non-communicable diseases, and 10% from injuries. By 2010, this had shifted to 35%, 54%, and 11%, respectively. Ischaemic heart disease was the leading cause of DALYs worldwide in 2010 (up from fourth rank in 1990, increasing by 29%), followed by lower respiratory infections (top rank in 1990; 44% decline in DALYs), stroke (fifth in 1990; 19% increase), diarrhoeal diseases (second in 1990; 51% decrease), and HIV/AIDS (33rd in 1990; 351% increase). Major depressive disorder increased from 15th to 11th rank (37% increase) and road injury from 12th to 10th rank (34% increase). Substantial heterogeneity exists in rankings of leading causes of disease burden among regions. INTERPRETATION: Global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with disability. In sub-Saharan Africa, however, many communicable, maternal, neonatal, and nutritional disorders remain the dominant causes of disease burden. The rising burden from mental and behavioural disorders, musculoskeletal disorders, and diabetes will impose new challenges on health systems. Regional heterogeneity highlights the importance of understanding local burden of disease and setting goals and targets for the post-2015 agenda taking such patterns into account. Because of improved definitions, methods, and data, these results for 1990 and 2010 supersede all previously published Global Burden of Disease results. FUNDING: Bill & Melinda Gates Foundation.

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.

Public health strategies for preventing and controlling overweight and obesity in school and worksite settings: a report on recommendations of the Task Force on Community Preventive Services.

Reducing morbidity and mortality related to overweight and obesity is a public health priority. Various interventions in school and worksite settings aim to maintain or achieve healthy weight. To identify effective strategies for weight control that can be implemented in these settings, the Task Force on Community Preventive Services (Task Force) has conducted systematic reviews of the evidence on nutrition, physical activity, combinations of these interventions, and other behavioral interventions (e.g., cognitive techniques such as self-awareness and cue recognition). Task Force recommendations are based on evidence of effectiveness, which is defined in this report as achieving a mean weight loss of > or =4 pounds, measured > or =6 months after initiation of the intervention program. The Task Force recommends multicomponent interventions that include nutrition and physical activity (including strategies such as providing nutrition education or dietary prescription, physical activity prescription or group activity, and behavioral skills development and training) to control overweight and obesity among adults in worksite settings. The Task Force determined that insufficient evidence existed to determine the effectiveness of combination nutrition and physical activity interventions to prevent or reduce overweight and obesity in school settings because of the limited number of qualifying studies reporting noncomparable outcomes. This report describes the methods used in these systematic reviews; provides additional information regarding these recommendations; and cites sources for full reviews containing details regarding applicability, other benefits and harms, barriers to implementation, research gaps, and economic data (when available) regarding interventions.

Methods for conducting systematic reviews of the evidence of effectiveness and economic efficiency of interventions to promote healthy social environments.

The social and physical surroundings in which people live affect their health. Knowing what basic conditions and opportunities in communities advance or impede improvement of community health can inform public health practice and policy. This article describes the methods for conducting systematic literature reviews of three community interventions to promote healthy social environments: early childhood development programs, programs to promote affordable family housing in safe neighborhoods, and interventions to increase the cultural and linguistic competence of healthcare systems. Existing methods, established for conducting systematic reviews for the Guide to Community Preventive Services, were applied to these interventions to promote healthy social environments.

Culturally competent healthcare systems. A systematic review.

Culturally competent healthcare systems-those that provide culturally and linguistically appropriate services-have the potential to reduce racial and ethnic health disparities. When clients do not understand what their healthcare providers are telling them, and providers either do not speak the client's language or are insensitive to cultural differences, the quality of health care can be compromised. We reviewed five interventions to improve cultural competence in healthcare systems-programs to recruit and retain staff members who reflect the cultural diversity of the community served, use of interpreter services or bilingual providers for clients with limited English proficiency, cultural competency training for healthcare providers, use of linguistically and culturally appropriate health education materials, and culturally specific healthcare settings. We could not determine the effectiveness of any of these interventions, because there were either too few comparative studies, or studies did not examine the outcome measures evaluated in this review: client satisfaction with care, improvements in health status, and inappropriate racial or ethnic differences in use of health services or in received and recommended treatment.

The effectiveness of early childhood development programs. A systematic review.

Early childhood development is influenced by characteristics of the child, the family, and the broader social environment. Physical health, cognition, language, and social and emotional development underpin school readiness. Publicly funded, center-based, comprehensive early childhood development programs are a community resource that promotes the well-being of young children. Programs such as Head Start are designed to close the gap in readiness to learn between poor children and their more economically advantaged peers. Systematic reviews of the scientific literature demonstrate effectiveness of these programs in preventing developmental delay, as assessed by reductions in retention in grade and placement in special education.

Providing affordable family housing and reducing residential segregation by income. A systematic review.

The inadequate supply of affordable housing for low-income families and the increasing spatial segregation of some households by income, race, ethnicity, or social class into unsafe neighborhoods are among the most prevalent community health concerns related to family housing. When affordable housing is not available to low-income households, family resources needed for food, medical or dental care, and other necessities are diverted to housing costs. Two housing programs intended to provide affordable housing and, concurrently, reduce the residential segregation of low-income families into unsafe neighborhoods of concentrated poverty, are reviewed: the creation of mixed-income housing developments and the Department of Housing and Urban Development (HUD) Section 8 Rental Voucher Program. The effectiveness of mixed-income housing developments could not be ascertained by this systematic review because of a lack of comparative research. Scientific evidence was sufficient to conclude that rental voucher programs improve household safety as measured by reduced exposure to crimes against person and property and decreased neighborhood social disorder. Effectiveness of rental voucher programs on youth health risk behaviors, mental health status, and physical health status could not be determined because too few studies of adequate design and execution reported these outcomes.

[Using evidence to assess the effectiveness of health promotion programs: a few fundamental issues]. / Utiliser des données probantes pour évaluer l'efficacité de la promotion de la santé: quelques enjeux fondamentaux.

This paper first discusses more generally the notion of "evidence" and then applies it to the field of health promotion. It is argued that health promotion has not yet reached the status of a fully recognised and recognisable discipline, borrowing many of its theoretical and methodological approaches from apparatuses to a wide variety of established other disciplines. Consequently, developing "evidence-based" practices in health promotion, as in biomedicine for example, is problematic on many counts and leaves three major issues unsolved. These issues are addressed and the authors conclude on an optimistic note, despite the serious problems that still remain to be solved.

The global burden of ischemic stroke: findings of the GBD 2010 study.

This study sought to summarize the findings of the GBD 2010 (Global Burden of Diseases, Injuries, and Risk Factors) study for ischemic stroke (IS) and to report the impact of tobacco smoking on IS burden in specific countries. The GBD 2010 searched multiple databases to identify relevant studies published between 1990 and 2010. The GBD 2010 analytical tools were used to calculate region-specific IS incidence, mortality, mortality-to-incidence ratio, and disability-adjusted life years (DALY) lost, including 95% uncertainty intervals (UI). In 2010, there were approximately 11,569,000 incident IS events (63% in low- and middle-income countries [LMIC]), approximately 2,835,000 deaths from IS (57% in LMIC), and approximately 39,389,000 DALY lost due to IS (64% in LMIC). From 1990 to 2010, there was a significant increase in global IS burden in terms of absolute number of people with incident IS (37% increase), deaths from IS (21% increase), and DALY lost due to IS (18% increase). Age-standardized IS incidence, DALY lost, mortality, and mortality-to-incidence ratios in high-income countries declined by about 13% (95% UI: 6% to 18%), 34% (95% UI: 16% to 36%), and 37% (95% UI: 19% to 39%), 21% (95% UI: 10% to 27%), respectively. However, in LMIC there was a modest 6% increase in the age-standardized incidence of IS (95% UI: -7% to 18%) despite modest reductions in mortality rates, DALY lost, and mortality-to-incidence ratios. There was considerable variability among country-specific estimates within broad GBD regions. China, Russia, and India were ranked highest in both 1990 and 2010 for IS deaths attributable to tobacco consumption. Although age-standardized IS mortality rates have declined over the last 2 decades, the absolute global burden of IS is increasing, with the bulk of DALY lost in LMIC. Tobacco consumption is an important modifiable risk factor for IS, and in both 1990 and 2010, the top ranked countries for IS deaths that could be attributed to tobacco consumption were China, Russia, and India. Tobacco control policies that target both smoking initiation and smoking cessation can play an important role in the prevention of IS. In China, Russia, and India, even modest reductions in the number of current smokers could see millions of lives saved due to prevention of IS alone.

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.

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

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.

Using logic models to capture complexity in systematic reviews.

Logic models have long been used to understand complex programs to improve social and health outcomes. They illustrate how a program is designed to achieve its intended outcomes. They also can be used to describe connections between determinants of outcomes, for example, low high-school graduation rates or spiraling obesity rates, thus aiding the development of interventions that target causal factors. However, these models have not often been used in systematic reviews. This paper argues that logic models can be valuable in the systematic review process. First, they can aid in the conceptualization of the review focus and illustrate hypothesized causal links, identify effect mediators or moderators, specify intermediate outcomes and potential harms, and justify a priori subgroup analyses when differential effects are anticipated. Second, logic models can be used to direct the review process more specifically. They can help justify narrowing the scope of a review, identify the most relevant inclusion criteria, guide the literature search, and clarify interpretation of results when drawing policy-relevant conclusions about review findings. We present examples that explain how logic models have been used and how they can be applied at different stages in a systematic review. Copyright © 2011 John Wiley & Sons, Ltd.

The effectiveness of worksite nutrition and physical activity interventions for controlling employee overweight and obesity: a systematic review.

This report presents the results of a systematic review of the effectiveness of worksite nutrition and physical activity programs to promote healthy weight among employees. These results form the basis for the recommendation by the Task Force on Community Preventive Services on the use of these interventions. Weight-related outcomes, including weight in pounds or kilograms, BMI, and percentage body fat were used to assess effectiveness of these programs. This review found that worksite nutrition and physical activity programs achieve modest improvements in employee weight status at the 6-12-month follow-up. A pooled effect estimate of -2.8 pounds (95% CI=-4.6, -1.0) was found based on nine RCTs, and a decrease in BMI of -0.5 (95% CI=-0.8, -0.2) was found based on six RCTs. The findings appear to be applicable to both male and female employees, across a range of worksite settings. Most of the studies combined informational and behavioral strategies to influence diet and physical activity; fewer studies modified the work environment (e.g., cafeteria, exercise facilities) to promote healthy choices. Information about other effects, barriers to implementation, cost and cost effectiveness of interventions, and research gaps are also presented in this article. The findings of this systematic review can help inform decisions of employers, planners, researchers, and other public health decision makers.