3,258 research outputs found
Ethical issues in implementation research: a discussion of the problems in achieving informed consent
No full textBackground: Improved quality of care is a policy objective of health care systems around the world. Implementation research is the scientific study of methods to promote the systematic uptake of clinical research findings into routine clinical practice, and hence to reduce inappropriate
care. It includes the study of influences on healthcare professionals' behaviour and methods to enable them to use research findings more effectively. Cluster randomized trials represent the optimal design for evaluating the effectiveness of implementation strategies. Various codes of
medical ethics, such as the Nuremberg Code and the Declaration of Helsinki inform medical research, but their relevance to cluster randomised trials in implementation research is unclear. This paper discusses the applicability of various ethical codes to obtaining consent in cluster trials in implementation research.
Discussion: The appropriate application of biomedical codes to implementation research is not obvious. Discussion of the nature and practice of informed consent in implementation research cluster trials must consider the levels at which consent can be sought, and for what purpose it can be sought. The level at which an intervention is delivered can render the idea of patient level
consent meaningless. Careful consideration of the ownership of information, and rights of access to and exploitation of data is required. For health care professionals and organizations, there is a balance between clinical freedom and responsibility to participate in research.
Summary: While ethical justification for clinical trials relies heavily on individual consent, for
implementation research aspects of distributive justice, economics, and political philosophy underlie the debate. Societies may need to trade off decisions on the choice between individualized consent and valid implementation research. We suggest that social sciences codes could usefully inform the consideration of implementation research by members of Research Ethics Committees
Analysing the rate of change in a longitudinal study with missing data, taking into account the number of contact attempts
No full textIn longitudinal and multivariate settings incomplete data, due to missed visits, dropouts or non-return of
questionnaires are quite common.
A longitudinal trial in which potentially informative missingness occurs is the Collaborative Ankle Support
Trial (CAST). The aim of this study is to estimate the clinical effectiveness of four different methods of
mechanical support after severe ankle sprain. The clinical status of multiple subjects was measured at four
points in time via a questionnaire and, based on this, a continuous and bounded outcome score was calculated.
Motivated by this study, a model is proposed for continuous longitudinal data with non-ignorable or
informative missingness, taking into account the number of attempts made to contact initial non-responders.
The model combines a non-linear mixed model for the underlying response model with a logistic regression
model for the reminder process.
The outcome model enables us to analyze the rate of improvement including the dependence on explanatory
variables. The non-linear mixed model is derived under the assumption that the rate of improvement in a given
time interval is proportional to the current score and the still achievable score. Based on this assumption a
differential equation is solved in order to obtain the model of interest.
The response model relates the probability of response at each contact attempt and point in time to
covariates and to observed and missing outcomes.
Using this model the impact of missingness on the rate of improvement is evaluated for different missingness
processes
Modelling the rate of change in a longitudinal study with missing data, adjusting for contact attempts
No full textThe Collaborative Ankle Support Trial (CAST) is a longitudinal trial in which interest lies in the rate of
improvement, the effectiveness of reminders and potentially informative missingness. A model is proposed for
continuous longitudinal data with non-ignorable or informative missingness, taking into account the nature of
attempts made to contact initial non-responders. The model combines a non-linear mixed model for the outcome\ud
model with a logistic regression model for the reminder process. A sensitivity analysis is used to contrast this
model with the traditional selection model, where we adjust for missingness by modelling the missingness process
Modelling health scores with the skew-normal distribution
No full textHealth care interventions which use quality of life or health scores often provide data
which are skewed and bounded. The scores are typically formed by adding up responses
to a number of questions. Different questions might have different weights, but the scores
will be bounded, and are often scaled to the range 0 to 100. If improvement in health
over time is measured, scores will tend to cluster near the 'healthy' or 'good' boundary
as time progresses, leading to a skew distribution. Further, some patients will drop out
as time progresses, so the scores reflect a selected population.
We fit models based on the skew-normal distribution to data from a randomised controlled trial of treatments for sprained ankles, in which scores were recorded at baseline
and 1, 3 and 9 months. We consider the extent to which skewness in the data can be
explained by the clustering at the boundary via a comparison between a censored normal
and a censored skew-normal model.
As this analysis is based on the complete data only, a formula for the distortion of
the treatment effects due to informative drop-out is given. This allows us to assess under
which conditions the conclusions drawn on the complete data may be either reinforced or
reversed, when the informative drop-out process is taken into account
Long-term survival for a cohort of adults with cerebral palsy
No full textThe aim of this study was to investigate long-term survival and examine causes of death in adult patients with cerebral palsy (CP). A 1940–1950 birth cohort based on paediatric case referral allows for long-term survival follow-up. Survival is analyzed by birth characteristics and severity of disability from age 20 years (and age 2y for a subset of the data). Survival outcome compared with that expected in the general population based on English life tables. The main cohort consisted of 341 individuals, with 193 males and 148 females. Conditional on surviving to age 20 years, almost 85% of the cohort survived to age 50 years (a comparable estimate for the general population is 96%). Very few deaths were attributed to CP for those people dying over 20 years of age. Females survived better than males. However, females faced a greater increase in risk relative to the general population than did males. We conclude that survival outlook is good though lower than in the general population. The relative risk of death compared with the UK population decreases with age, although it shows some indication of rising again after age 50 years. Many more deaths were caused by diseases of the respiratory system among those dying in their 20s and 30s than would be expected in the general population. Many fewer deaths than expected in this age group are caused by injuries and accidents. For those people who die in their 40s and 50s, an increase in deaths due to diseases of the circulatory system and neoplasms is observed. More deaths than expected in this age group are due to diseases of the nervous system
Intercollegiate Rifle & Tennis Teams 1938
No full textMounted black and white photo, with names.Back: JG Rudall, WO Graham, JW Reddin, C Slee, SC Williams; front: JI Wilkinson, JL Hutton, TWC Angove, Mr BC Philp (Manager), WH Jones, HM Martin
Reflections of a Jewish, Lesbian Author
No full textIn this essay, Jewish lesbian author Leslea Newman speaks of the importance of finding one's own identity reflected in works of literature, citing examples of her own work, and recommending the writings of other Jewish lesbian authors of merit
Number needed to treat: Properties and problems
No full textThe inverse of a difference in probabilities, called the \u27number needed to treat\u27, has been promoted in the medical literature as a good way to present the results of modelling binary outcomes. The usual context is randomized controlled trials and meta-analyses. In this paper we discuss the claims that have been made about this statistic, and the problems associated with it. Methods which have been proposed for confidence intervals are evaluated and shown to be erroneous. We suggest that the difference in probabilities, the \u27absolute risk reduction\u27, is preferable to the number needed to treat, for both theoretical and practical reasons
Are distinctive ethical principles required for cluster randomized controlled trials?
No full textCluster randomized trials are increasingly used in research into health care and health services. Ethics of individual patient randomized trials have been elucidated in a number of different codes, but less attention has been given to the ethical issues raised by cluster randomized trials. I assess the challenges raised by cluster randomized controlled trials by considering three questions: What are the essential elements of ethical medical research, particularly experiments on people? What are the features which distinguish cluster randomized controlled trials from ordinary RCTs? Do the distinctive features of cluster randomized trials entail new ethical principles, or careful application of existing principles? I conclude that cluster randomized controlled trials raise new issues on the nature and practice of informed consent, because of the levels at which consent can be sought, and for which it can be sought. In addition, careful consideration of the principles relating to the quality of the scientific design and analysis, balance of risk and benefit, liberty to leave a trial, early stopping of a trial and the power to exclude people from potential benefits is required. Copyright \ua9 2001 John Wiley & Sons, Ltd
Ethics of medical research in developing countries: The role of international codes of conduct
No full textMany statisticians work with informal codes of ethics, and are probably unaware of the existence or content of rules which have been drawn up to govern statistical practice. Medical statisticians will be aware of codes of conduct for medical research, and most codes of professional ethics have some dependence on evidence. Statisticians, therefore, have a valuable contribution to make to debates on ethics which concern scientific soundness, data and perceptions of risk. A lively debate on the revision of the widely respected Declaration of Helsinki, to reflect issues arising from research in developing countries, particularly HIV research, centres on questions of study design, data analysis and assessment of risk. Collectively owned multiprofessional work requires each of the various professions to take responsibility for the conduct of the research, and the impact that it might have. Statisticians share important responsibilities in maintaining ethical medical research in all countries
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