Particular Outcome (particular + outcome)

Distribution by Scientific Domains


Selected Abstracts


Quantifying the impact of survivor treatment bias in observational studies

JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 6 2006
Peter C. Austin PhD
Abstract Rationale, Observational cohort studies are frequently used to measure the impact of therapies on the time to a particular outcome. Treatment often has a time-variant nature since it is frequently initiated at varying times during a patient's follow-up. Studies in the medical literature frequently ignore the time-dependent nature of treatment exposure. Survivor treatment bias can arise when the time dependent nature of treatment exposure is ignored since patients who survived to receive treatment may be healthier than patients who died prior to receipt of treatment. Aims and objectives, The objective of the current study was to explicitly quantify the magnitude of survivor-treatment bias. Methods, Monte Carlo simulations using parameters obtained from an analysis of patients admitted to hospital with a diagnosis of acute myocardial infarction in Ontario, Canada. Results and conclusions, When the true treatment was null (hazard ratio of 1), estimated treatment effects varied from a 4% reduction in mortality to a reduction in mortality of 27% when the time varying nature of the treatment was ignored. Furthermore, survivor-treatment bias increased as the time required foe exposed patients to receive treatment increased. Similarly, survivor treatment bias was amplified as exposure was defined to be exposure at any time prior to mortality compared to exposure within a fixed time interval starting at the time origin. Ignoring the time-dependent nature of treatment results in overly optimistic estimates of treatment effects. Depending on the period required for patients to initiate therapy, treatments with no effect on survival can appear to be strongly associated with improved survival. The current study is the first to explicitly quantify the magnitude of bias that results from ignoring the time-varying nature of treatment exposure in survival studies. [source]


Joint generalized estimating equations for multivariate longitudinal binary outcomes with missing data: an application to acquired immune deficiency syndrome data

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2009
Stuart R. Lipsitz
Summary., In a large, prospective longitudinal study designed to monitor cardiac abnormalities in children born to women who are infected with the human immunodeficiency virus, instead of a single outcome variable, there are multiple binary outcomes (e.g. abnormal heart rate, abnormal blood pressure and abnormal heart wall thickness) considered as joint measures of heart function over time. In the presence of missing responses at some time points, longitudinal marginal models for these multiple outcomes can be estimated by using generalized estimating equations (GEEs), and consistent estimates can be obtained under the assumption of a missingness completely at random mechanism. When the missing data mechanism is missingness at random, i.e. the probability of missing a particular outcome at a time point depends on observed values of that outcome and the remaining outcomes at other time points, we propose joint estimation of the marginal models by using a single modified GEE based on an EM-type algorithm. The method proposed is motivated by the longitudinal study of cardiac abnormalities in children who were born to women infected with the human immunodeficiency virus, and analyses of these data are presented to illustrate the application of the method. Further, in an asymptotic study of bias, we show that, under a missingness at random mechanism in which missingness depends on all observed outcome variables, our joint estimation via the modified GEE produces almost unbiased estimates, provided that the correlation model has been correctly specified, whereas estimates from standard GEEs can lead to substantial bias. [source]


Genetics of cardiovascular diseases: An overview

NURSING & HEALTH SCIENCES, Issue 2 2005
Carmen T Ramirez edd, acnp(c), apn-g(c)
Cardiovascular disease is the leading cause of illness and death in the USA, as well as other countries. Advances in genetics have led researchers to identified associations between a number of cardiac syndromes and diagnostic molecular findings. Therefore, a more precise understanding of the molecular pathways involved in cardiovascular diseases is clinically significant. Current literature suggests that while etiologies remain complex, a number of cardiovascular diseases can be linked to specific metabolic inheritable factors. A broad multifactorial model is gradually being replaced with disease specific models where independent genetic and/or teratogenic pathways may lead to a particular outcome. These genetic pathways include chromosome deletions, disruptions (translocations), duplications of particular genetic regions, point mutations involving single genes, or alteration in the ability for a gene to be transcribed into a functional protein. In this review the molecular mechanisms underlying cardiovascular diseases and their clinical manifestations will be explained. [source]


Childhood trauma and marital outcomes in adulthood

PERSONAL RELATIONSHIPS, Issue 4 2006
MARK A. WHISMAN
Although existing research suggests that certain childhood traumas such as childhood sexual abuse are associated with interpersonal (e.g., marital) difficulties in adulthood, there has been limited research on interpersonal sequelae of other types of traumas. In addition, the association between childhood traumas and interpersonal outcomes has often been limited to a particular outcome such as divorce, and existing studies have rarely controlled for the co-occurrence of other traumas when evaluating interpersonal outcomes. The current study sought to evaluate the associations between 7 childhood traumas and 2 marital outcomes,marital disruption (i.e., divorce and separation) and marital satisfaction,in a large, national probability sample. Results from univariate and multivariate analyses indicated that (a) probability of marital disruption was higher among people who during childhood had experienced physical abuse, rape, or serious physical attack or assault; and (b) current marital satisfaction was lower among people who during childhood had experienced rape or sexual molestation. Results support the importance of childhood traumas in predicting 2 important marital outcomes. [source]


PROBABILITY-BASED OPTIMAL DESIGN

AUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 1 2008
J. M. McGree
Summary Optimal design of experiments has generally concentrated on parameter estimation and, to a much lesser degree, on model discrimination. Often an experimenter is interested in a particular outcome and wishes to maximize in some way the probability of this outcome. We propose a new class of compound criteria and designs that address this issue for generalized linear models. The criteria offer a method of achieving designs that possess the properties of efficient parameter estimation and a high probability of a desired outcome. [source]


The impact of exposure to domestic violence on children and young people: a review of the literature

CHILD: CARE, HEALTH AND DEVELOPMENT, Issue 6 2008
Richard Reading
The impact of exposure to domestic violence on children and young people: a review of the literature HoltS., BuckleyH. & WhelanS. ( 2008 ) Child Abuse & Neglect , 32 , 797 , 810 . Objective This article reviews the literature concerning the impact of exposure to domestic violence on the health and developmental well-being of children and young people. Impact is explored across four separate yet interrelated domains (domestic violence exposure and child abuse, impact on parental capacity, impact on child and adolescent development and exposure to additional adversities), with potential outcomes and key messages concerning best practice responses to children's needs highlighted. Method A comprehensive search of identified databases was conducted within an 11-year framework (1995,2006). This yielded a vast literature that was selectively organized and analysed according to the four domains identified above. Results This review finds that children and adolescents living with domestic violence are at increased risk of experiencing emotional, physical and sexual abuse, of developing emotional and behavioural problems and of increased exposure to the presence of other adversities in their lives. It also highlights a range of protective factors that can mitigate against this impact, in particular a strong relationship with and attachment to a caring adult, usually the mother. Conclusion Children and young people may be significantly affected by living with domestic violence, and impact can endure even after measures have been taken to secure their safety. It also concludes that there is rarely a direct causal pathway leading to a particular outcome and that children are active in constructing their own social world. Implications for interventions suggest that timely, appropriate and individually tailored responses need to build on the resilient blocks in the child's life. Practice implications This study illustrate the links between exposure to domestic violence, various forms of child abuse and other related adversities, concluding that such exposure may have a differential yet potentially deleterious impact for children and young people. From a resilient perspective this review also highlights range of protective factors that influence the extent of the impact of exposure and the subsequent outcomes for the child. This review advocates for a holistic and child-centred approach to service delivery, derived from an informed assessment, designed to capture a picture of the individual child's experience and responsive to their individual needs. [source]


Uncovering Local Perspectives on Humanitarian Assistance and Its Outcomes

DISASTERS, Issue 2 2000
Oliver Bakewell
This paper draws on a study of Angolan refugees in Zambia to suggest ways that the perspectives and interests of the local population can be included in the assessment of relief interventions. Taking an actor-oriented approach, the paper suggests stepping back from the categorisation of the situation as an emergency and particular groups of people as the beneficiaries. Such categories are imposed from outside and may not reflect local people's outlook on the situation. In the case of Angolans in Zambia, the category of refugees had dissolved in the border villages to the extent that it was practically impossible to distinguish between refugees and hosts. This was in contrast to the official settlements where people were marked out as refugees and the label was maintained and reproduced over many years. Investigating outcomes in the border villagers in terms of refugees and the refugee problem would have been futile. The paper calls for evaluations of humanitarian assistance in complex emergencies to look beyond the ,beneficiaries' and to investigate the wider context of ,normality'. Neglecting the life and world of local people will make it impossible to understand the process by which external interventions are mediated at the local level to give particular outcomes, and valuable lessons which could help alleviate suffering will be lost. [source]


IS EVOLUTIONARY BIOLOGY STRATEGIC SCIENCE?

EVOLUTION, Issue 1 2007
Thomas R. Meagher
There is a profound need for the scientific community to be better aware of the policy context in which it operates. To address this need, Evolution has established a new Outlook feature section to include papers that explore the interface between society and evolutionary biology. This first paper in the series considers the strategic relevance of evolutionary biology. Support for scientific research in general is based on governmental or institutional expenditure that is an investment, and such investment is based on strategies designed to achieve particular outcomes, such as advance in particular areas of basic science or application. The scientific community can engage in the development of scientific strategies on a variety of levels, including workshops to explicitly develop research priorities and targeted funding initiatives to help define emerging scientific areas. Better understanding and communication of the scientific achievements of evolutionary biology, emphasizing immediate and potential societal relevance, are effective counters to challenges presented by the creationist agenda. Future papers in the Outlook feature section should assist the evolutionary biology community in achieving a better collective understanding of the societal relevance of their field. [source]


Self-Compassion Versus Global Self-Esteem: Two Different Ways of Relating to Oneself

JOURNAL OF PERSONALITY, Issue 1 2009
Kristin D. Neff
ABSTRACT This research examined self-compassion and self-esteem as they relate to various aspects of psychological functioning. Self-compassion entails treating oneself with kindness, recognizing one's shared humanity, and being mindful when considering negative aspects of oneself. Study 1 (N=2,187) compared self-compassion and global self-esteem as they relate to ego-focused reactivity. It was found that self-compassion predicted more stable feelings of self-worth than self-esteem and was less contingent on particular outcomes. Self-compassion also had a stronger negative association with social comparison, public self-consciousness, self-rumination, anger, and need for cognitive closure. Self-esteem (but not self-compassion) was positively associated with narcissism. Study 2 (N=165) compared global self-esteem and self-compassion with regard to positive mood states. It was found that the two constructs were statistically equivalent predictors of happiness, optimism, and positive affect. Results from these two studies suggest that self-compassion may be a useful alternative to global self-esteem when considering what constitutes a healthy self-stance. [source]


Parental mental health: disruptions to parenting and outcomes for children

CHILD & FAMILY SOCIAL WORK, Issue 1 2004
Marjorie Smith
ABSTRACT The association between parental mental health problems and negative outcomes for children has been long known. This paper addresses three issues in relation to this. First, the scale of the problem is outlined, in terms of both the prevalence of mental health problems in parents and the likelihood of children exhibiting negative outcomes in these circumstances. Secondly, the specificity, or lack of it, of particular outcomes in the child in relation to different parental mental health problems is explored. Thirdly, the paper focuses on the importance of disruptions to parenting as a mechanism in the transmission of mental health problems to negative impacts on the child. Examples are given of how parenting is disrupted in non-clinical community populations, and the subsequent impacts on the child. The case is made for the preventative importance of parenting and family support in mediating between parental mental health problems and negative impacts on the child. [source]