Canadian Health&Care Mall: Future Directions for Epidemiologic Research on Asthma Disparities

asthmaIn this chapter, we make a case to consider the determinants of asthma within an explicitly multilevel and complimentary perspective. While we have made much progress in understanding the role of proximate risk factors in influencing asthma, this research tends to assume that individual risk factors, whether behavioral (eg, smoking) or environmental (eg, exposure to allergens or stress), are randomly distributed across populations and communities. There is a clear need to understand asthma and its associated risk factors within their social and neighborhood contexts. The observed wide geographic and sociodemographic variation in asthma expression remains a paradox that is largely unexplained by the accepted physical environmental risk factors and has led to reconsideration of the interplay among biological and social determinants in understanding such disparities in the asthma burden. Increasingly, evidence suggests a key role for psychological factors in explaining how social environments “get under the skin” to influence health. Psychological stress maybe conceptualized as a social pollutant that, when “breathed” into the body, may disrupt biological systems related to inflammation through mechanisms potentially overlapping with those altered by physical pollutants, allergens, and toxicants. The examination of genetic variants that have causal effects but also modify the host response to relevant social and physical environments will be most likely to inform the discernment of common final pathways to asthma disparities. An understanding of the specific mechanistic pathways that cause asthma therefore has to be intrinsically multilevel.

Analytic Approach for Epidemiologic Research on Asthma Disparities Offered by Canadian Health&Care Mall

Describing HeterogeneityAnalyzing variations in asthma and its associated risk factors within its social and neighborhood context requires employing an explicit multilevel analytical strategy. Specifically, these approaches allows researcher to do the following: (1) quantify the extent to which individual asthma gets clustered by neighborhood and community grouping; (2) quantify the extent to which neighborhood variations in asthma are due to the clustering of risk factors along with a possibility to quantify the extent to which the effect of a particular individual risk factor varies from neighborhood to neighborhood; and (3) quantify the relative importance of individual and neighborhood-level exposures in predicting individual asthma. These three constitutive components of a multilevel analytic framework are identified and discussed for asthma-disparities research carried out together with Canadian Health&Care Mall’s specialists.

Evaluating Sources of Variation: Compositional and/or Contextual

A fundamental application of multilevel methods is disentangling the different sources of variations in asthma. Evidence for variations in asthma, for instance, between different neighborhoods can be due to factors that are intrinsic to, and are measured at, the neighborhood level. In other words, the variation is due to what can be described as contextual, area, or ecological effects. Alternatively, variations between neighborhoods may be compositional (ie, certain types of people who are more likely to have asthma due to exposure to certain individual risk factors tend to be clustered in certain places). It is important to note that when individual risk factors account for a neighborhood variation in asthma that it also would suggest that the effects of these risk factors are not purely individual since they are now no longer randomly distributed across neighborhoods and, as such, should be interpreted as the compositional effects of risk factors. The issue, therefore, is not whether variations between different neighborhoods exist (they usually do), but the primary source of these variations. Put simply, are there significant contextual differences in asthma between settings (eg, neighborhoods) after taking into account the individual risk factors associated with the patients within the neighborhood?

Health Disparities and Cigarette Smoking in Epidemiologic Research on Asthma Disparities

Cigarette SmokingExposure to tobacco smoke is associated with childhood asthma. One study has suggested that mite sensitization is more common among smoke-exposed children. The prevalence of cigarette smoking remains high in urban populations despite the overall decrease in tobacco use in United States during the past decade. Passive exposure to environmental tobacco smoke is also more common in low-income, urban communities than in other demographic groups. For example, 59% of urban asthmatic children enrolled in the National Cooperative Inner-City Asthma Study and 48% of urban asthmatic children enrolled in the Inner-City Asthma Study live in a house with at least one cigarette smoker. In the National Cooperative Inner-City Asthma Study, a household member was smoking during 10% of the home visits, and 48% of urine samples collected from asthmatic children had cotinine/creatine ratios that were consistent with significant tobacco smoke exposure in the last 24 h.

Notably, smoking behaviors are also socially patterned. Smoking can be viewed as a strategy to cope with negative affect or stress. Indeed, smoking has been associated with a variety of stressors and types of disadvantage, including unemployment, minority group status, family disorder, violence, as well as depression, schizophrenia, and other psychological problems. Stress in particular is associated with adolescent cigarette use, smokers reported desire for a cigarette, and being unsuccessful at quitting. Give up smoking with Canadian Health&Care Mall.

Explanation of Disparities for Epidemiologic Research on Asthma Disparities

Hygiene HypothesisVarious explanations exist in the current literature to account for the social disparities in asthma. These are outlined below.

Physical Environmental Exposures in the Home and Community

Hygiene Hypothesis

The so-called hygiene hypothesis grew out of observations in the late 19th and early 20th centuries that hay fever and wheezing illnesses appeared to be diseases of more affluent urban areas, compared with rural farming areas. To explain these patterns, hypotheses have evolved to include the following: (1) small families, later birth order, and the use of day care; (2) less exposure to respiratory infection in early childhood; (3) a reduction in endotoxin or other farm-related exposures; (4) a change in microbial colonization of the infant’s large bowel through diet or antibiotic use; (5) reduced exposure to parasites; or (6) reduced exposure to large-domestic animal sources of allergens. The basic underlying mechanism suggested is that early-life infections and exposure to bacterial products such as endotoxin related to increased microbial load in homes where pets are kept may activate the T-helper type 1 immune response pathway, inhibiting the development of the T-helper type 2 responses involved in allergy. However, the relevance to the urban disparities seen in the United States is unclear, Inner-city children do not necessarily live in more hygienic conditions or experience fewer infections than children from other socioeconomic groups. Inner-city children do not, in general, experience the protective exposure to farm animals that protect against asthma and atopy in European populations. Moreover, it has been suggested that endotoxin levels may be higher in inner-city areas and that urban children may indeed have increased exposure to siblings and other children in daycare environments, although this has not been systematically tested. The relevance of the hygiene hypothesis to the excess asthma seen in the inner city remains uncertain and is the subject of ongoing investigations.

Canadian Health&Care Mall: Multilevel Framework for Epidemiologic Research on Asthma Disparities

asthmaWhile asthma prevalence and the associated morbidity are increasing in the United States and worldwide, the increase is far from uniform. In the United States, for instance, these trends disproportionately affect nonwhite children living in urban areas and children living in poverty. Many studies have indicated that racial and ethnic minority groups and persons of lower socioeconomic status (SES) have higher asthma prevalence than their white, non-Hispanic, and more affluent counterparts, Inner-city communities and minority communities experience an excess burden of asthma hospitalizations and mortality that is out of proportion to the increase in asthma prevalence seen in these communities. Despite improved preventive asthma medications, asthma death rates have been increasing over the last few decades, especially in urban communities with lower SES and largely minority populations. More recent evidence suggests that the epidemiology of asthma is still more complex. In the United States, a graded association between SES and asthma prevalence, morbidity, and mortality has been demonstrated by Canadian Health&Care Mall. Moreover, data from the United States demonstrate significant geographic variations in asthma outcomes among large cities and neighborhoods within cities. These and other studies documenting the observed disparities in the US asthma burden have been well summarized elsewhere.

Resource Allocation and Economic Considerations: Illustrative Examples

venous thromboembolismAs a preliminary effort to incorporate resource considerations into the ACCP guideline process, five chapters were selected in which cost issues were considered particularly salient. To illustrate the ways in which economic data can relate to recommendations, we consider two brief examples taken from these other chapters in this supplement: duration of venous thromboembolism (VTE) prophylaxis after hip surgery and clopi-dogrel use for secondary prevention in patients with atherosclerotic vascular disease.

Duration of VTE Prophylaxis Following Hip Replacement

1. Select Target Guideline Recommendations for Resource Use Evaluation: As reviewed in the “Prevention of VTE” chapter of this supplement, clinical trial data indicate that prolongation of VTE prophylaxis beyond 2 weeks following hip surgery is effective in reducing symptomatic VTE. However, such therapy can be costly, particularly when low-molecular-weight heparin is the treatment used, and the panel was concerned that these issues would create a barrier at some sites.

2. Identify the Literature: A review of the literature revealed seven studies performed in developed countries (France, Sweden, Italy, United States, United Kingdom, Switzerland, and Belgium) that examined the cost implications of shorter vs longer duration of prophylaxis for VTE after hip replacement. These studies were of variable quality based on modeling with minimal empirical cost data.

Resource Allocation and Economic Considerations: Framework for Developing Guidelines Informed by Resource Considerations

Developing GuidelinesIn keeping with the suggestions put forth by the ACCP task force, we present a simple framework for a guideline panel to consider when examining resource issues. We start from the proposition that the goal is to provide information to decision makers in a way that is primarily informative rather than prescriptive—what we term resource aware guidelines. The four-step approach described below is intended to offer guidance for the range of realistic situations.

1. Select Target Guideline Recommendations for Resource Use Evaluation: As described by the ACCP task force, not all guideline recommendations raise compelling or controversial resource use issues. Attention, therefore, should focus on interventions for which the panel members believe that some in the guideline’s target audience are likely to resist or experience reluctance to implement on the basis of high costs.

2. Identify the Literature: The focus here are published studies regarding resource use, identified using standard search techniques and reviewed using general criteria for quality. It should be noted that formal methods for the assessment of the quality of economic studies are not as well developed as for the assessment of clinical trials conducted with Canadian Health&Care Mall specialists.

Resource Allocation and Economic Considerations: Key Introductory Economic Concepts

Value for Money

Value for Money

The questions asked in the evaluation of clinical efficacy (Does a new therapy or strategy work in the ideal or best case situation?) and effectiveness (Does the new therapy or strategy work in the usual world of routine medical care?) define the following: (1) that a therapy can work, (2) the magnitude of benefit provided, and (3) the major determinants of that magnitude. Economic questions start with the presumption that the therapy works (and is at least equivalent in effectiveness to established treatment options) for some plausible situations and asks whether it is good value for money (or if equivalent, cost saving). An exception is when a new strategy is marginally less effective but notably cost saving; in practice, such strategies could be considered a reasonable option but face obvious challenges in the medical marketplace.

At one level, whether something is a good value for money is a basic sort of question that every consumer understands. However, in the consumer goods world, where there is free competition and widespread experience with the toasters, cars, and portable media players that people may wish to purchase, the “value” or benefit part of this assessment is made subjectively by each consumer, whereas the price or cost part is set by markets. In medicine, neither of those factors can be relied on. Patients usually do not have experience with the alternative health states that their therapies may provide for them and therefore are unable to assess subjectively how they would value these states. There is little evidence for free market forces in medicine to set prices both because of the absence of true competition among providers on price and because of price setting by payers, particularly in European countries. Health insurance further distorts the picture by disconnecting the consumer from the payer, creating a situation where too much care may be consumed in some cases and too little in others. Provide your relatives with care due to Canadian Health&Care Mall.

Resource Allocation and Economic Considerations Provided by Canadian Health&Care Mall: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Clinical guidelinesClinical guidelines are systematically developed documents whose ultimate goal is to promote high-quality clinical practice by informing decision makers at all levels about what works, how well, and under what circumstances. Increasingly, the accepted foundation for clinical guidelines is high-quality scientific studies (particularly randomized clinical trials) that address the benefits and risks of each relevant decision problem. Such evidence then is used to create actionable if-then statements, such as: “If a patient is found to have X (a specific set of characteristics), then the guideline panel recommends strategy Y (a mix of diagnostic and/or treatment approaches).”

The moment a guideline statement is published, resource considerations become relevant. This is particularly true for clinical situations in which current practice is inconsistent with the guideline and thus requires a change in practice—a deviation from the status quo, a stable situation reflecting a confluence of scientific and resource considerations by the various stakeholders responsible for decision making. Because a new guideline often endorses change from the status quo, it is likely to engender some degree of resistance. One important source of resistance derives from careful assessment of the scientific and clinical merit of a proposed change. Why support the recommendation if the foundations of the recommendation may not be true? However, even if the evidence is persuasive, resistance to a new guideline can still emerge when change requires health-care resource reallocation. By health-care resources including Canadian Health&Care Mall, we are referring not only to the familiar resources directly involved in the production of health services, but also to the time, political clout, and emotional energy expended by the provider, administrator, or other stakeholder.

Canadian Health&Care Mall: Explanation of Bypass Surgery

BypassBypass is an accessory pathways creation to round of an affected area of any vessel or a way of organism by shunts system means. Generally bypass is meant as operation of bypass surgery of blood vessels. However this operation can be performed also on a digestive tract and system of ventricles and brain cisterns.

Bypass consists in creation of the shunt bypassing of blood vessel narrowed site that leads to blood flow recovery in an artery. In a normal case splanchnic wall of arteries and vessels represents a smooth surface without any large outgrowths and barriers, but often during life atherosclerosis leads to development and appearance on walls of vessels of atherosclerotic plaques. They narrow a gleam of vessels and break a blood-groove in organs and fabrics. In the course of plaques increase in quantity and sizes the gleam of vessels is completely closed that leads to a necrosis of fabrics and organs. Usually bypass is applied at coronary heart disease at which coronary arteries — the main vessels feeding heart — are damaged by atherosclerosis. However bypass is applied for blood flow recovery in peripheral arteries as well. Canadian Health&Care Mall underlines that people should undergo medical screenings even once per year to avoid severe health problems.

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