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A Study Of Joinpoint Models For Longitudinal Data, Libo Zhou 2014 University of Nevada, Las Vegas

A Study Of Joinpoint Models For Longitudinal Data, Libo Zhou

UNLV Theses, Dissertations, Professional Papers, and Capstones

In many medical studies, data are collected simultaneously on multiple biomarkers from each individual. Levels of these biomarkers are measured periodically over certain time duration, giving rise to longitudinal trajectories. The subjects under study may also be subject to dropout due to several competing causes, the likelihood of which may be affected by the levels of these biomarkers. In this dissertation, we investigate flexible Bayesian modeling of such data, taking into account any available covariate information as well as possible censoring of the drop-out times. We propose joint models for multiple biomarkers with multiple causes of dropout. Our proposed models ...


Randomized Clinical Trial To Evaluate The Pathogenicity Of Bibersteinia Trehalosi In Respiratory Disease Among Calves, Christy Jo Hanthorn, Reneé Dewell, Vickie L. Cooper, Timothy S. Frana, Paul J. Plummer, Chong Wang, Grant A. Dewell 2014 Iowa State University

Randomized Clinical Trial To Evaluate The Pathogenicity Of Bibersteinia Trehalosi In Respiratory Disease Among Calves, Christy Jo Hanthorn, Reneé Dewell, Vickie L. Cooper, Timothy S. Frana, Paul J. Plummer, Chong Wang, Grant A. Dewell

Veterinary Diagnostic and Production Animal Medicine Publications

Bibersteinia trehalosi causes respiratory disease in ruminants particularly in wild and domestic sheep. Recently, there has been an increased number of B. trehalosi isolates obtained from diagnostic samples from bovine respiratory disease cases. This study evaluated the role of B. trehalosi in bovine respiratory disease using an intra-tracheal inoculation model in calves. Thirty six cross bred 2–3 month old dairy calves were inoculated intra-tracheally with either leukotoxin negative B. trehalosi, leukotoxin positive B. trehalosi isolate, Mannheimia haemolytica, a combination of leukotoxin negative B. trehalosi and M. haemolytica or negative control. Calves were euthanized and necropsy performed on day 10 ...


Nudging The Fda, W. Nicholson Price II, I. Glenn Cohen 2014 University of New Hampshire School of Law

Nudging The Fda, W. Nicholson Price Ii, I. Glenn Cohen

Law Faculty Scholarship

[Excerpt] "The FDA’s regulation of drugs is frequently the subject of policy debate, with arguments falling into two camps. On the one hand, a libertarian view of patients and the health care system holds high the value of consumer choice. Patients should get all the information and the drugs they want; the FDA should do what it can to enforce some basic standards but should otherwise get out of the way. On the other hand, a paternalist view values the FDA’s role as an expert agency standing between patients and a set of potentially dangerous drugs and potentially ...


Dose Expansion Cohorts In Phase I Trials, Alexia Iasonos, John O'Quigley 2014 Memorial Sloan Kettering Cancer Center

Dose Expansion Cohorts In Phase I Trials, Alexia Iasonos, John O'Quigley

Alexia Iasonos

A rapidly increasing number of Phase I dose-finding studies, and in particular those based on the standard 3+3 design, frequently prolong the study and include dose expansion cohorts (DEC) with the goal to better characterize the toxicity profiles of experimental agents and to study disease specific cohorts. These trials consist of two phases: the usual dose escalation phase that aims to establish the maximum tolerated dose (MTD) and the dose expansion phase that accrues additional patients, often with different eligibility criteria, and where additional information is being collected. Current protocols typically do not specify whether the MTD will be ...


Circulating Cardiac Troponin T Exhibits A Diurnal Rhythm, Lieke J. J. Klinkenberg, Jan-Willem van Dijk, Frans E. S. Tan, Luc J.C. van Loon, Marja P. van Dieijen-Visser, Steven J. R. Meex 2014 Australian Catholic University

Circulating Cardiac Troponin T Exhibits A Diurnal Rhythm, Lieke J. J. Klinkenberg, Jan-Willem Van Dijk, Frans E. S. Tan, Luc J.C. Van Loon, Marja P. Van Dieijen-Visser, Steven J. R. Meex

Faculty of Health Sciences Publications

Objectives The goal of this study was to test the unverified assumption that chronically elevated cardiac troponin T (cTnT) levels fluctuate randomly around a homeostatic set point. Background The introduction of high-sensitivity cardiac troponin (cTn) assays has improved sensitivity for acute myocardial infarction (AMI). However, many patients with a single positive cTn test result do not have AMI. Therefore, the diagnosis of AMI relies strongly on serial testing and interpretation of cTn kinetics. Essential in this regard is a profound understanding of the biological variation of cTn. Methods Two studies were conducted to assess biological cTnT variation and to investigate ...


Clinical Project Management Portal Optimization Through Change Management Best Practices, Bridget C. Moty 2013 University of North Texas Health Science Center of Fort Worth

Clinical Project Management Portal Optimization Through Change Management Best Practices, Bridget C. Moty

Theses and Dissertations

Purpose: The aim of this practicum project was 1) to determine the perceived benefits of, opinion of, and desire to use portals in a CRO; 2) to identify portal upgrade features based on user opinions and suggestions that can enhance communication and increase the transparency of data, and 3) to measure any changes in perceived benefits of, opinion of, and desire to use company portals after demonstration of a proposed upgraded portal model.

Hypothesis: Incorporating end users’ input to optimize portal design will (1) elicit more positive opinions about portal technology and its use, and (2) increase end users’ desire ...


Hypothesis Testing For An Extended Cox Model With Time-Varying Coefficients, Takumi Saegusa, Chongzhi Di, Ying Qing Chen 2013 University of Washington - Seattle Campus

Hypothesis Testing For An Extended Cox Model With Time-Varying Coefficients, Takumi Saegusa, Chongzhi Di, Ying Qing Chen

UW Biostatistics Working Paper Series

The log-rank test has been widely used to test a treatment effect under the Cox model for censored time-to-event outcomes, though it may lose power substantially when the model's proportional hazards assumption does not hold. In this paper, we consider an extended Cox model that uses B-splines or smoothing splines to model a time-varying treatment effect and propose score test statistics for the treatment effect. Our proposed new tests combine statistical evidence from both the magnitude and the shape of the time-varying hazard ratio function, and thus are omnibus and powerful against various types of alternatives. In addition, the ...


The Unseen And Untold Issues Of Clinical Trials And Research Ethics In Pakistan., Shahan Waheed, Emaduddin Siddiqui 2013 Aga Khan University

The Unseen And Untold Issues Of Clinical Trials And Research Ethics In Pakistan., Shahan Waheed, Emaduddin Siddiqui

Department of Emergency Medicine

No abstract provided.


Pilot Comparative Effectiveness Study Of Surface Perturbation Treadmill Training To Prevent Falls In Older Adults, Jon D. Lurie, Alexandra B. Zagaria, Dawna M. Pidgeon, Judith L. Forman, Kevin Spratt 2013 Dartmouth College

Pilot Comparative Effectiveness Study Of Surface Perturbation Treadmill Training To Prevent Falls In Older Adults, Jon D. Lurie, Alexandra B. Zagaria, Dawna M. Pidgeon, Judith L. Forman, Kevin Spratt

Open Dartmouth: Faculty Open Access Articles

Falls are the leading cause of fatal and non-fatal injuries among older adults. Exercise programs appear to reduce fall risk, but the optimal type, frequency, and duration of exercise is unknown. External perturbations such as tripping and slipping are a major contributor to falls, and task-specific perturbation training to enhance dynamic stability has emerged as a promising approach to modifying fall risk. The purpose of this pilot study was 1) to determine the feasibility of conducting a large pragmatic randomized trial comparing a multidimensional exercise program inclusive of the surface perturbation treadmill training (SPTT) to multidimensional exercise alone (Standard PT ...


Future Vision For The Quality Assurance Of Oncology Clinical Trials, Thomas J. Fitzgerald, Maryann Bishop-Jodoin, Walter R. Bosch, Walter J. Curran, David S. Followill, James M. Galvin, Richard Hanusik, Steven R. King, Michael V. Knopp, Fran Laurie, Elizabeth O'Mear, Jeff M. Michalski, Joel H. Saltz, Mitchell D. Schnall, Lawrence Schwartz, Kenneth Ulin, Ying Xiao, Marcia Urie 2013 University of Massachusetts Medical School

Future Vision For The Quality Assurance Of Oncology Clinical Trials, Thomas J. Fitzgerald, Maryann Bishop-Jodoin, Walter R. Bosch, Walter J. Curran, David S. Followill, James M. Galvin, Richard Hanusik, Steven R. King, Michael V. Knopp, Fran Laurie, Elizabeth O'Mear, Jeff M. Michalski, Joel H. Saltz, Mitchell D. Schnall, Lawrence Schwartz, Kenneth Ulin, Ying Xiao, Marcia Urie

University of Massachusetts Medical School Faculty Publications

The National Cancer Institute clinical cooperative groups have been instrumental over the past 50 years in developing clinical trials and evidence-based process improvements for clinical oncology patient care. The cooperative groups are undergoing a transformation process as we further integrate molecular biology into personalized patient care and move to incorporate international partners in clinical trials. To support this vision, data acquisition and data management informatics tools must become both nimble and robust to support transformational research at an enterprise level. Information, including imaging, pathology, molecular biology, radiation oncology, surgery, systemic therapy, and patient outcome data needs to be integrated into ...


An Evaluation Of Inferential Procedures For Adaptive Clinical Trial Designs With Pre-Specified Rules For Modifying The Sample Size, Greg P. Levin, Sarah C. Emerson, Scott S. Emerson 2013 University of Washington, Seattle Campus

An Evaluation Of Inferential Procedures For Adaptive Clinical Trial Designs With Pre-Specified Rules For Modifying The Sample Size, Greg P. Levin, Sarah C. Emerson, Scott S. Emerson

UW Biostatistics Working Paper Series

Many papers have introduced adaptive clinical trial methods that allow modifications to the sample size based on interim estimates of treatment effect. There has been extensive commentary on type I error control and efficiency considerations, but little research on estimation after an adaptive hypothesis test. We evaluate the reliability and precision of different inferential procedures in the presence of an adaptive design with pre-specified rules for modifying the sampling plan. We extend group sequential orderings of the outcome space based on the stage at stopping, likelihood ratio test statistic, and sample mean to the adaptive setting in order to compute ...


Sas Macro: Kappa Statistic For Clustered Matched-Pair Data, Zhao Yang 2013 Quintiles Inc

Sas Macro: Kappa Statistic For Clustered Matched-Pair Data, Zhao Yang

Zhao (Tony) Yang, Ph.D.

The SAS macro was developed to calculate the kappa statistic for the clustered matched-pair data.


Dose-Response And Finding In Phase Ii Clinical Studies — Mcp-Mod Methodologies, Zhao Yang 2013 Quintiles Inc

Dose-Response And Finding In Phase Ii Clinical Studies — Mcp-Mod Methodologies, Zhao Yang

Zhao (Tony) Yang, Ph.D.

This presentation give an overall introduction to the MCP-Mod methodology with detailed step-by-step demonstration.


On The Exact Size Of Multiple Comparison Tests, Chris Lloyd 2012 Melbourne Business School

On The Exact Size Of Multiple Comparison Tests, Chris Lloyd

Chris J. Lloyd

No abstract provided.


On The Size Accuracy Of Combination Tests, Chris Lloyd 2012 Melbourne Business School

On The Size Accuracy Of Combination Tests, Chris Lloyd

Chris J. Lloyd

One element of the analysis of adaptive clinical trials is combining the evidence from several (often two) stages. When the endpoint is binary, standard single stage tests statistics do not control size well. Yet the combined test might not be valid if the single stage tests are not. The purpose of this paper is to numerically and theoretically examine the extent to which combining basic tests statistics mitigates or magnifies the size violation of the final test.


Big Data And The Future, Sherri Rose 2012 Johns Hopkins Bloomberg School of Public Health

Big Data And The Future, Sherri Rose

Sherri Rose

No abstract provided.


Bayesian Adaptive Designs For Early Phase Clinical Trials, Chunyan Cai 2012 The University of Texas Graduate School of Biomedical Sciences at Houston

Bayesian Adaptive Designs For Early Phase Clinical Trials, Chunyan Cai

UT GSBS Dissertations and Theses (Open Access)

My dissertation focuses mainly on Bayesian adaptive designs for phase I and phase II clinical trials. It includes three specific topics: (1) proposing a novel two-dimensional dose-finding algorithm for biological agents, (2) developing Bayesian adaptive screening designs to provide more efficient and ethical clinical trials, and (3) incorporating missing late-onset responses to make an early stopping decision.

Treating patients with novel biological agents is becoming a leading trend in oncology. Unlike cytotoxic agents, for which toxicity and efficacy monotonically increase with dose, biological agents may exhibit non-monotonic patterns in their dose-response relationships. Using a trial with two biological agents as ...


Targeted Maximum Likelihood Estimation For Dynamic Treatment Regimes In Sequential Randomized Controlled Trials, Paul Chaffee, Mark J. van der Laan 2012 University of California, Berkeley, Division of Biostatistics

Targeted Maximum Likelihood Estimation For Dynamic Treatment Regimes In Sequential Randomized Controlled Trials, Paul Chaffee, Mark J. Van Der Laan

Paul H. Chaffee

Sequential Randomized Controlled Trials (SRCTs) are rapidly becoming essential tools in the search for optimized treatment regimes in ongoing treatment settings. Analyzing data for multiple time-point treatments with a view toward optimal treatment regimes is of interest in many types of afflictions: HIV infection, Attention Deficit Hyperactivity Disorder in children, leukemia, prostate cancer, renal failure, and many others. Methods for analyzing data from SRCTs exist but they are either inefficient or suffer from the drawbacks of estimating equation methodology. We describe an estimation procedure, targeted maximum likelihood estimation (TMLE), which has been fully developed and implemented in point treatment settings ...


Adaptive Randomization Designs, Jenna Colavincenzo 2012 California Polytechnic State University - San Luis Obispo

Adaptive Randomization Designs, Jenna Colavincenzo

Statistics

Adaptive design methodologies use prior information to develop a clinical trial design. The goal of an adaptive design is to maintain the integrity and validity of the study while giving the researcher flexibility in identifying the optimal treatment. An example of an adaptive design can be seen in a basic pharmaceutical trial. There are three phases of the overall trial to compare treatments and experimenters use the information from the previous phase to make changes to the subsequent phase before it begins.

Adaptive design methods have been in practice since the 1970s, but have become increasingly complex ever since. One ...


Estimating The Impact Of Community-Level Interventions: The Search Trial And Hiv Prevention In Sub-Saharan Africa, Laura Balzer, Maya Petersen, Joshua Schwab, Mark van der Laan 2012 University of California, Berkeley

Estimating The Impact Of Community-Level Interventions: The Search Trial And Hiv Prevention In Sub-Saharan Africa, Laura Balzer, Maya Petersen, Joshua Schwab, Mark Van Der Laan

Laura B. Balzer

Evaluation of community level interventions to prevent HIV infection presents significant methodological challenges. Even when it is feasible to randomly assign a treatment versus control level of the intervention to each community in a sample, measurement of incident HIV infection remains difficult. In this talk we describe an experimental design developed for the SEARCH Trial, a large community randomized trial that will evaluate the impact of expanded treatment on incident HIV and other outcomes. Regular community-wide testing campaigns are conducted and a random sample of community members who fail to attend a campaign are tracked. The data generated by this ...


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