Estimates of the Statistics of Randomly Varying Parameters of Linear Systems

Mathematical model used in estimating statistics of randomly varying parameters of linear system

Usability and feasibility of PreventS-MD webapp for stroke prevention.

BACKGROUND: Most strokes and cardiovascular diseases (CVDs) are potentially preventable if their risk factors are identified and well controlled. Digital platforms, such as the PreventS-MD webapp (PreventS-MD) may aid health care professionals (HCPs) in assessing and managing risk factors and promoting lifestyle changes for their patients. METHODS: This is a mixed methods cross-sectional 2-phase survey using a largely positivist (quantitative and qualitative) framework. During phase 1, a prototype of PreventS-MD was tested internationally by 59 of 69 consenting HCPs of different backgrounds, age, sex, working experience and specialities using hypothetical data. Collected comments/suggestions from the study HCPs in phase 1 were reviewed and implemented. In phase 2, a near-final version of PreventS-MD was developed and tested by 58 of 72 consenting HCPs using both hypothetical and real patient (n=10) data. Qualitative semi-structured interviews with real patients (n=10) were conducted, and 1-month adherence to the preventative recommendations was assessed by self-reporting. The four System Usability Scale (SUS) groups of scores (0-50 unacceptable; 51-68 poor, 68-80.3 good; >80.3 excellent) were used to determine usability of PreventS-MD. FINDINGS: 99 HCPs from 27 countries (45% from low- to middle-income countries) participated in the study, out of whom 10 HCPs were involved in the development of PreventS before the study, and therefore were not involved in the survey. Of the remaining 89 HCPs 69 consented to the first phase of the survey, out of whom 59 completed the first phase of the survey (response rate 86%) and 58 HCPs completed the second phase of the survey (response rate 84%). The SUS scores supported good usability of the prototype (mean score=80.2; 95% CI [77.0-84.0]) and excellent usability of the final version of PreventS-MD (mean score=81.7; 95%CI [79.1-84.3]) in the field. Scores were not affected by the age, sex, working experience or speciality of the HCPs. One month follow-up of the patients confirmed the high level of satisfaction/acceptability of PreventS-MD and (100%) adherence to the recommendations. INTERPRETATION: The PreventS-MD webapp has a high level of usability, feasibility and satisfaction by HCPs and individuals at risk of stroke/CVD. Individuals at risk of stroke/CVD demonstrated a high level of confidence and motivation in following and adhering to preventative recommendations generated by PreventS-MD

Big data and data repurposing – using existing data to answer new questions in vascular dementia research

Introduction: Traditional approaches to clinical research have, as yet, failed to provide effective treatments for vascular dementia (VaD). Novel approaches to collation and synthesis of data may allow for time and cost efficient hypothesis generating and testing. These approaches may have particular utility in helping us understand and treat a complex condition such as VaD. Methods: We present an overview of new uses for existing data to progress VaD research. The overview is the result of consultation with various stakeholders, focused literature review and learning from the group’s experience of successful approaches to data repurposing. In particular, we benefitted from the expert discussion and input of delegates at the 9th International Congress on Vascular Dementia (Ljubljana, 16-18th October 2015). Results: We agreed on key areas that could be of relevance to VaD research: systematic review of existing studies; individual patient level analyses of existing trials and cohorts and linking electronic health record data to other datasets. We illustrated each theme with a case-study of an existing project that has utilised this approach. Conclusions: There are many opportunities for the VaD research community to make better use of existing data. The volume of potentially available data is increasing and the opportunities for using these resources to progress the VaD research agenda are exciting. Of course, these approaches come with inherent limitations and biases, as bigger datasets are not necessarily better datasets and maintaining rigour and critical analysis will be key to optimising data use

Multi-level community interventions for primary stroke prevention: A conceptual approach by the World Stroke Organization

The increasing burden of stroke and dementia emphasizes the need for new, well-tolerated and cost-effective primary prevention strategies that can reduce the risks of stroke and dementia worldwide, and specifically in low- and middle-income countries (LMICs). This paper outlines conceptual frameworks of three primary stroke prevention strategies: (a) the “polypill” strategy; (b) a “population-wide” strategy; and (c) a “motivational population-wide” strategy. (a) A polypill containing generic low-dose ingredients of blood pressure and lipid-lowering medications (e.g. candesartan 16 mg, amlodipine 2.5 mg, and rosuvastatin 10 mg) seems a safe and cost-effective approach for primary prevention of stroke and dementia. (b) A population-wide strategy reducing cardiovascular risk factors in the whole population, regardless of the level of risk is the most effective primary prevention strategy. A motivational population-wide strategy for the modification of health behaviors (e.g. smoking, diet, physical activity) should be based on the principles of cognitive behavioral therapy. Mobile technologies, such as smartphones, offer an ideal interface for behavioral interventions (e.g. Stroke Riskometer app) even in LMICs. (c) Community health workers can improve the maintenance of lifestyle changes as well as the adherence to medication, especially in resource poor areas. An adequate training of community health workers is a key point

Risk factors and in-hospital outcomes in stroke and myocardial infarction patients

BACKGROUND: Acute stroke (AS) and acute myocardial infarction (AMI) share major risk factors such as age, gender, and high blood pressure. The main objective of this study was to compare vascular risk factor profiles with in-hospital outcomes in AS and AMI patients. METHODS: We evaluated 486 consecutive patients who were admitted to Bjelovar General Hospital with diagnoses of AS (ischaemic stroke or intracerebral haemorrhage; N = 380) or AMI (N = 106) during a one year period. The frequency of risk factors and in-patient mortality rates were assessed in both groups. For statistical analysis we used t-tests and χ(2 )tests. RESULTS: AS patients were significantly older than AMI patients: the mean age for AS patients was 68.9 ± 9.1 years, and for AMI patients was 62.8 ± 11.7 years (p < 0.001). AMI was significantly more common than AS in patients younger than 65 years; 51% of this group had AMI and 26% had AS (p < 0.001). Hypertension was a more common risk factor in AS patients (69% AS patients vs. 58% AMI patients; p = 0.042). Patients who died did not differ significantly in age between the groups. In-patient mortality rates were significantly higher in AS than AMI cases (31% vs. 12%, p < 0.001 for all patients; 37% vs.5%, p < 0.001 for men). Women hospitalized for AMI were more likely to die in hospital than men (28% vs. 5%; p = 0.002). CONCLUSIONS: We found that age at the time of presentation was a significant differentiating factor between patients with AS and AMI. The only exceptions were women, whose ages at the onset of AS and AMI were similar. In contrast, patients who died did not differ significantly in age. We observed significantly higher inpatient mortality for men (when adjusted for age) than for women with AS. The five-fold higher in-patient mortality rate in women than in men with AMI is most likely to have resulted from other factors related to treatment

Heart failure associated with imported malaria:a nationwide Danish cohort study

Abstract Aims Despite adequate treatment, recent studies have hypothesized that malaria may affect long‐term cardiovascular function. We aimed to investigate the long‐term risk of cardiovascular events and death in individuals with a history of imported malaria in Denmark. Methods Using nationwide Danish registries, we followed individuals with a history of malaria for the risk of incident heart failure (HF), myocardial infarction (MI), cardiovascular death and all‐cause death (1 January 1994 to 1 January 2017). The population was age‐ and sex‐matched with individuals without a history of malaria from the Danish population (ratio 1:9). We excluded patients with known HF and ischaemic heart disease at inclusion. Results We identified 3912 cases with a history of malaria (mean age 33 ± 17 years, 57% male, 41% Plasmodium falciparum infections). The median follow‐up was 9.8 years (interquartile range 3.9–16.4 years). Event rates per 1000 person‐years for individuals with a history vs. no history of malaria were HF: 1.84 vs. 1.32; MI: 1.28 vs. 1.30; cardiovascular death: 1.40 vs. 1.77; and all‐cause death: 5.04 vs. 5.28. In Cox proportional hazards models adjusted for cardiovascular risk factors, concomitant pharmacotherapy, region of origin, household income and educational level, malaria was associated with HF (HR: 1.59 [1.21–2.09], P = 0.001), but not MI (HR: 1.00 [0.72–1.39], P = 1.00), cardiovascular death (HR: 1.00 [0.74–1.35], P = 0.98) or all‐cause death (HR 1.11 [0.94–1.30], P = 0.21). Specifically, P. falciparum infection was associated with increased risk of HF (HR: 1.64 [1.14–2.36], P = 0.008). Conclusion Individuals with a history of imported malaria, specifically P. falciparum, may have an increased risk of incident HF

Surveillance of trend and distribution of stroke mortality by subtype, age, gender, and geographic areas in Tianjin, China, 1999–2006

The purpose of this study was to analyze the epidemiological trend and distribution of stroke mortality in the city of Tianjin, China, in order to provide evidence for the prevention and control of stroke. Methods The study was based on 102 718 cases of stroke mortality in Tianjin between 1999 and 2006. The cause of death was coded according to the International Classification of Diseases into stroke subtypes. Standardized mortality rates were calculated for stroke and its subtypes, adjusted for age and gender using the year 2000 world standard population. The age, gender, and geographic distribution of stroke and subtype mortality were analyzed. Χ 2 -tests were used to determine the statistical significance of differences in mortality trends. Results The stroke mortality rate in Tianjin declined from 133·52/100 000/year in 1999 to 102·52/100 000/year in 2006. The stroke mortality rate for males was higher than that for females. Stroke mortality rates increased with increasing age. The subtypes of stroke have changed considerably in Tianjin. Hemorrhagic was major in 1999–2001, while cerebral infarction attained the first rank and accounted for more than 50% of stroke mortality in 2002–2006. The most pronounced finding was that the proportion of ischemic stroke was 66·65% in the urban population and over 20% higher than that in the rural area. Stroke in the suburban area was mainly hemorrhagic stroke, up to 62·67%. Conclusions There are significant differences in the distribution of stroke mortality by subtype, age, gender, and geographic areas in Tianjin, China. Various subtypes of stroke are associated with different risk factors and therefore require different public health prevention and control measures. This study provides pertinent information for formulation of measures for the prevention and control of stroke.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72496/1/j.1747-4949.2009.00272.x.pd

Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015

SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation

Non-pharmacological interventions for post-stroke emotionalism (PSE) within inpatient stroke settings: a theory of planned behavior survey

Background: Post-stroke emotionalism (PSE) is common. Trials of antidepressants for PSE suggest only modest clinical benefit and risk of side effects. There have been no trials of non-pharmacological treatments for PSE; in fact, little is known about the non-pharmacological treatments actually provided to PSE sufferers in clinical practice. Objectives: To determine the non-pharmacological interventions provided by stroke professionals, their perceived effectiveness, and the factors associated with the intention to provide them. Methods: Focus groups and published sources of information were used to construct a comprehensive list of non-pharmacological approaches for PSE. This was followed by a national (online) survey of 220 UK stroke clinicians from nursing, medicine, and the allied health professions to investigate the approaches used in clinical practice, using Theory of Planned Behavior components to determine the factors associated with intention to provide them. Results: Most respondents reported high intention to provide non-pharmacological interventions from the list that was constructed. Offering reassurance and talking to patients about goals were the commonest interventions, and distraction and tensing facial muscles least common. Respondents who perceived others to hold them professionally responsible for carrying out non-pharmacological approaches were more likely to use them, as were respondents who held more positive attitudes. Conclusions: Our survey data reveal that stroke clinicians report regular use of non-pharmacological interventions for PSE. There is a pressing need for well-conducted clinical trials to evaluate the effectiveness of these approaches

The role of steroids in the management of brain metastases: a systematic review and evidence-based clinical practice guideline

Do steroids improve neurologic symptoms in patients with metastatic brain tumors compared to no treatment? If steroids are given, what dose should be used? Comparisons include: (1) steroid therapy versus none. (2) comparison of different doses of steroid therapy. Target population These recommendations apply to adults diagnosed with brain metastases. Recommendations Steroid therapy versus no steroid therapy Asymptomatic brain metastases patients without mass effect Insufficient evidence exists to make a treatment recommendation for this clinical scenario. Brain metastases patients with mild symptoms related to mass effect Level 3 Corticosteroids are recommended to provide temporary symptomatic relief of symptoms related to increased intracranial pressure and edema secondary to brain metastases. It is recommended for patients who are symptomatic from metastatic disease to the brain that a starting dose of 4–8 mg/day of dexamethasone be considered. Brain metastases patients with moderate to severe symptoms related to mass effect Level 3 Corticosteroids are recommended to provide temporary symptomatic relief of symptoms related to increased intracranial pressure and edema secondary to brain metastases. If patients exhibit severe symptoms consistent with increased intracranial pressure, it is recommended that higher doses such as 16 mg/day or more be considered. Choice of Steroid Level 3 If corticosteroids are given, dexamethasone is the best drug choice given the available evidence. Duration of Corticosteroid Administration Level 3 Corticosteroids, if given, should be tapered slowly over a 2 week time period, or longer in symptomatic patients, based upon an individualized treatment regimen and a full understanding of the long-term sequelae of corticosteroid therapy. Given the very limited number of studies (two) which met the eligibility criteria for the systematic review, these are the only recommendations that can be offered based on this methodology. Please see “Discussion” and “Summary” section for additional details