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Surrogate Outcomes (surrogate + outcome)

Distribution by Scientific Domains
Medical Sciences75%

Terms modified by Surrogate Outcomes

  • surrogate outcome measure
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    Selected Abstracts

    Use of Surrogate Outcomes for Cardiovascular Disease After Renal Transplantation

    AMERICAN JOURNAL OF TRANSPLANTATION, Issue 11 2003
    Kevin C. Abbott
    No abstract is available for this article. [source]

    Related Causal Frameworks for Surrogate Outcomes

    BIOMETRICS, Issue 2 2009
    Marshall M. Joffe
    Summary Four major frameworks have been developed for evaluating surrogate markers in randomized trials: one based on conditional independence of observable variables, another based on direct and indirect effects, a third based on a meta-analysis, and a fourth based on principal stratification. The first two of these fit into a paradigm we call the causal-effects (CE) paradigm, in which, for a good surrogate, the effect of treatment on the surrogate, combined with the effect of the surrogate on the clinical outcome, allow prediction of the effect of the treatment on the clinical outcome. The last two approaches fall into the causal-association (CA) paradigm, in which the effect of the treatment on the surrogate is associated with its effect on the clinical outcome. We consider the CE paradigm first, and consider identifying assumptions and some simple estimation procedures; we then consider the CA paradigm. We examine the relationships among these approaches and associated estimators. We perform a small simulation study to illustrate properties of the various estimators under different scenarios, and conclude with a discussion of the applicability of both paradigms. [source]

    A "cure" for Parkinson's disease: Can neuroprotection be proven with current trial designs?

    MOVEMENT DISORDERS, Issue 5 2004
    Carl E. Clarke BSc
    Abstract Current medical and surgical therapies for Parkinson's disease provide symptomatic control of motor impairments rather than slowing or halting the progression of the disease. Previous clinical trials examining drugs such as dopamine agonists and selegiline for neuroprotective effects used "surrogate" outcomes, including clinical measures (rating scales, time to require levodopa), neuroimaging techniques (,-CIT single photon emission computed tomography; fluorodopa positron emission tomography), and mortality tracking. These studies failed to provide conclusive results because of design faults such as failing to control for symptomatic effects, small sample size, and not accounting for the possible effects of drugs on radionuclide tracer handling. Lessons must be learned from these failed neuroprotection trials. This review summarises the problems with previous neuroprotection studies and makes recommendations for future trial design. It is concluded that the primary outcome of explanatory trials should continue to be clinical measures such as the Unified Parkinson's Disease Rating Scale (UPDRS). It should be assumed that all agents have a symptomatic effect, which necessitates evaluation after a prolonged drug washout period. To achieve the evaluation after a prolonged drug washout period more effectively, trials must be performed in early disease and over a short period (6,12 months) so that symptomatic therapy is not required. To achieve adequate statistical power, these trials will need to include thousands of patients. Radionuclide imaging can only be used in such trials after considerable methodological work has been performed to establish its validity and reliability. To be affordable, such large explanatory trials need more streamlined designs with fewer hospital visits, fewer outcome measures, and rationalised safety monitoring. The clinical effectiveness of promising compounds from explanatory trials will need to be established in large long-term pragmatic trials using outcome measures such as quality of life, cost-effectiveness, and mortality. Such pragmatic trials could be continuations of the explanatory trials: after the primary outcome of the explanatory study (e.g., UPDRS) has been reported in an interim analysis, the trial could be continued for a further 5 to 10 years to report on quality of life and health economics outcomes. © 2004 Movement Disorder Society [source]

    Randomized controlled trial of SPIRIT: An effective approach to preparing African-American dialysis patients and families for end of life,

    RESEARCH IN NURSING & HEALTH, Issue 3 2009
    Mi-Kyung Song
    Abstract This randomized controlled trial tested an intervention, Sharing Patients' Illness Representations to Increase Trust (SPIRIT), designed to enhance communication regarding end-of-life care between African Americans with end-stage renal disease (ESRD) and their chosen surrogate decision makers (N,=,58 dyads). We used surveys and semi-structured interviews to determine the feasibility, acceptability, and preliminary effects of SPIRIT on patient and surrogate outcomes at 1 week and 3 months post-intervention. We also evaluated patients' deaths and surrogates' end-of-life decision making to assess surrogates' perceptions of benefits and limitations of the SPIRIT while facing end-of-life decisions. We found that SPIRIT promoted communication between patients and their surrogates and was effective and well received by the participants. © 2009 Wiley Periodicals, Inc. Res Nurs Health 32:260,273, 2009 [source]