Summary 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 Bank's 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.
Summary 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 non-significantly. 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 first 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.
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. Funding Bill & Melinda Gates Foundation.
China initiated major health-care reforms in 2009 aiming to provide universal health care for all by 2020. However, little is known about trends in health-care use and health outcomes across ...different socioeconomic groups in the past decade.
We used data from the China Kadoorie Biobank (CKB), a nationwide prospective cohort study of adults aged 30–79 years in 2004–08, in ten regions (five urban, five rural) in China. Individuals who were alive in 2009 were included in the present study. Data for all admissions were obtained by linkage to electronic hospital records from the health insurance system, and to region-specific disease and death registers. Generalised linear models were used to estimate trends in annual hospital admission rates, 28-day case fatality rates, and mean length of stay for stroke, ischaemic heart disease, and any cause in all relevant individuals.
512 715 participants were recruited to the CKB between June 25, 2004, and July 15, 2008, 505 995 of whom were still alive on Jan 1, 2009, and contributed to the present study. Among them, we recorded 794 824 hospital admissions (74 313 for stroke, 69 446 for ischaemic heart disease) between 2009 and 2016. After adjustment for demographic, socioeconomic, lifestyle, and morbidity factors, hospitalisation rates increased annually by 3·6% for stroke, 5·4% for ischaemic heart disease, and 4·2% for any cause, between 2009 and 2016. Higher socioeconomic groups had higher hospitalisation rates, but the annual proportional increases were higher in those with lower education or income levels, those enrolled in the urban or rural resident health insurance scheme, and for those in rural areas. Lower socioeconomic groups had higher case fatality rates for stroke and ischaemic heart disease, but greater reductions in case fatality rates than higher socioeconomic groups. By contrast, mean length of stay decreased by around 2% annually for stroke, ischaemic heart disease, and any cause, but decreased to a greater extent in higher than lower socioeconomic groups for stroke and ischaemic heart disease.
Between 2009 and 2016, lower socioeconomic groups in China had greater increases in hospital admission rates and greater reductions in case fatality rates for stroke and ischaemic heart disease. Additional strategies are needed to further reduce socioeconomic differences in health-care use and disease outcomes.
Wellcome Trust, Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, China Ministry of Science and Technology, and Chinese National Natural Science Foundation.
Abstract Objectives This study sought to evaluate in-hospital outcomes and 3-year mortality of patients presenting with unprotected left main stem occlusion (ULMSO) treated with primary percutaneous ...coronary intervention (PPCI). Background Limited data exists about management and outcome following presentation with ULMSO. Methods From January 1, 2007 to December 21, 2012, 446,257 PCI cases were recorded in the British Cardiovascular Intervention Society database of all PCI cases in England and Wales. Of those, 568 were patients having emergency PCI for ST-segment elevation infarction (0.6% of all PPCI) who presented with ULMSO (TIMI Thrombolysis In Myocardial Infarction flow grade 0/1 and stenosis >75%), and they were compared with 1,045 emergency patients treated with nonocclusive LMS disease. Follow-up was obtained through linkage with the Office of National Statistics. Results Presentation with ULMSO, compared with nonocclusive LMS disease, was associated with a doubling in the likelihood of periprocedural shock (57.9% vs. 27.9%; p < 0.001) and/or intra-aortic balloon pump support (52.5% vs. 27.2%; p < 0.001). In-hospital (43.3% vs. 20.6%; p < 0.001), 1-year (52.8% vs. 32.4%; p < 0.001), and 3-year mortality (73.9% vs 52.3%, p < 0.001) rates were higher in patients with ULMSO, compared with patients presenting with a patent LMS, and were significantly influenced by the presence of cardiogenic shock. ULMSO and cardiogenic shock were independent predictors of 30-day (hazard ratio HR: 1.61 95% confidence interval (CI): 1.07 to 2.41, p = 0.02, and HR: 5.43 95% CI: 3.23 to 9.12, p<0.001, respectively) and 3-year all-cause mortality (HR: 1.52 95% CI: 1.06 to 2.17, p = 0.02, and HR: 2.98 95% CI: 1.99 to 4.49, p < 0.001, respectively). Conclusions In patients undergoing PPCI for ULMSO, acute outcomes are poor and additional therapies are required to improve outcome. However, long-term outcomes for survivors of ULMSO are encouraging.
This study sought to review the literature for risk prediction models in patients with heart failure and to identify the most consistently reported independent predictors of risk across models.
Risk ...assessment provides information about patient prognosis, guides decision making about the type and intensity of care, and enables better understanding of provider performance.
MEDLINE and EMBASE were searched from January 1995 to March 2013, followed by hand searches of the retrieved reference lists. Studies were eligible if they reported at least 1 multivariable model for risk prediction of death, hospitalization, or both in patients with heart failure and reported model performance. We ranked reported individual risk predictors by their strength of association with the outcome and assessed the association of model performance with study characteristics.
Sixty-four main models and 50 modifications from 48 studies met the inclusion criteria. Of the 64 main models, 43 models predicted death, 10 hospitalization, and 11 death or hospitalization. The discriminatory ability of the models for prediction of death appeared to be higher than that for prediction of death or hospitalization or prediction of hospitalization alone (p = 0.0003). A wide variation between studies in clinical settings, population characteristics, sample size, and variables used for model development was observed, but these features were not significantly associated with the discriminatory performance of the models. A few strong predictors emerged for prediction of death; the most consistently reported predictors were age, renal function, blood pressure, blood sodium level, left ventricular ejection fraction, sex, brain natriuretic peptide level, New York Heart Association functional class, diabetes, weight or body mass index, and exercise capacity.
There are several clinically useful and well-validated death prediction models in patients with heart failure. Although the studies differed in many respects, the models largely included a few common markers of risk.
Patients born outside the UK have contributed to a 20% rise in the UK's tuberculosis incidence since 2000, but their effect on domestic transmission is not known. Here we use whole-genome sequencing ...to investigate the epidemiology of tuberculosis transmission in an unselected population over 6 years.
We identified all residents with Oxfordshire postcodes with a Mycobacterium tuberculosis culture or a clinical diagnosis of tuberculosis between Jan 1, 2007, and Dec 31, 2012, using local databases and checking against the national Enhanced Tuberculosis Surveillance database. We used Illumina technology to sequence all available M tuberculosis cultures from identified cases. Sequences were clustered by genetic relatedness and compared retrospectively with contact investigations. The first patient diagnosed in each cluster was defined as the index case, with links to subsequent cases assigned first by use of any epidemiological linkage, then by genetic distance, and then by timing of diagnosis.
Although we identified 384 patients with a diagnosis of tuberculosis, country of birth was known for 380 and we sequenced isolates from 247 of 269 cases with culture-confirmed disease. 39 cases were genomically linked within 13 clusters, implying 26 local transmission events. Only 11 of 26 possible transmissions had been previously identified through contact tracing. Of seven genomically confirmed household clusters, five contained additional genomic links to epidemiologically unidentified non-household members. 255 (67%) patients were born in a country with high tuberculosis incidence, conferring a local incidence of 109 cases per 100,000 population per year in Oxfordshire, compared with 3·5 cases per 100,000 per year for those born in low-incidence countries. However, patients born in the low-incidence countries, predominantly UK, were more likely to have pulmonary disease (adjusted odds ratio 1·8 95% CI 1·2-2·9; p=0·009), social risk factors (4·4 2·0-9·4; p<0·0001), and be part of a local transmission cluster (4·8 1·6-14·8; p=0·006).
Although inward migration has contributed to the overall tuberculosis incidence, our findings suggest that most patients born in high-incidence countries reactivate latent infection acquired abroad and are not involved in local onward transmission. Systematic screening of new entrants could further improve tuberculosis control, but it is important that health care remains accessible to all individuals, especially high-risk groups, if tuberculosis control is not to be jeopardised.
UK Clinical Research Collaboration (Wellcome Trust, Medical Research Council, National Institute for Health Research NIHR), and NIHR Oxford Biomedical Research Centre.
Summary Background Some countries fortify flour with folic acid to prevent neural tube defects but others do not, partly because of concerns about possible cancer risks. We aimed to assess any ...effects on site-specific cancer rates in the randomised trials of folic acid supplementation, at doses higher than those from fortification. Methods In these meta-analyses, we sought all trials completed before 2011 that compared folic acid versus placebo, had scheduled treatment duration at least 1 year, included at least 500 participants, and recorded data on cancer incidence. We obtained individual participant datasets that included 49 621 participants in all 13 such trials (ten trials of folic acid for prevention of cardiovascular disease n=46 969 and three trials in patients with colorectal adenoma n=2652). All these trials were evenly randomised. The main outcome was incident cancer (ignoring non-melanoma skin cancer) during the scheduled treatment period (among participants who were still free of cancer). We compared those allocated folic acid with those allocated placebo, and used log-rank analyses to calculate the cancer incidence rate ratio (RR). Findings During a weighted average scheduled treatment duration of 5·2 years, allocation to folic acid quadrupled plasma concentrations of folic acid (57·3 nmol/L for the folic acid groups vs 13·5 nmol/L for the placebo groups), but had no significant effect on overall cancer incidence (1904 cancers in the folic acid groups vs 1809 cancers in the placebo groups, RR 1·06, 95% CI 0·99–1·13, p=0·10). There was no trend towards greater effect with longer treatment. There was no significant heterogeneity between the results of the 13 individual trials (p=0·23), or between the two overall results in the cadiovascular prevention trials and the adenoma trials (p=0·13). Moreover, there was no significant effect of folic acid supplementation on the incidence of cancer of the large intestine, prostate, lung, breast, or any other specific site. Interpretation Folic acid supplementation does not substantially increase or decrease incidence of site-specific cancer during the first 5 years of treatment. Fortification of flour and other cereal products involves doses of folic acid that are, on average, an order of magnitude smaller than the doses used in these trials. Funding British Heart Foundation, Medical Research Council, Cancer Research UK, Food Standards Agency.