Dissertations / Theses on the topic 'Randomized controlled trials'
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1
Glen, Peter. "Outcome Reporting in Surgical Randomized Controlled Trials." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34237.
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Background: In September 2005, scientific journals began requiring trial protocol registration to increase transparency and accountability.
Objective: My primary objectives were: develop a database of linked protocols and publications for surgical randomized control trials (RCTs); estimate the proportion published; and determine the proportion exhibiting selective outcome reporting.
Methods: A systematic search of the clinicaltrials.gov database was conducted identifying surgical RCTs, completed between 2006 and 2012. Protocols were linked with publications. Primary outcomes were compared.
Results: We identified a cohort of 743 surgical RCT protocols. The proportion of registered trials which published their primary results was 0.49 (n=364). The proportion of selective outcome reporting was estimated to be 0.244, significantly lower than the previous estimate (p<0.001).
Conclusion: More than half of the completed surgical RCTs were unpublished, and one quarter of those published selectively reported their primary outcome. This supports the notion that significant bias is present in the surgical literature.
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Spieth, Peter Markus, Anne Sophie Kubasch, Ana Isabel Penzlin, Ben Min-Woo Illigens, Kristian Barlinn, and Timo Siepmann. "Randomized controlled trials - a matter of design." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-215848.
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Randomized controlled trials (RCTs) are the hallmark of evidence-based medicine and form the basis for translating research data into clinical practice. This review summarizes commonly applied designs and quality indicators of RCTs to provide guidance in interpreting and critically evaluating clinical research data. It further reflects on the principle of equipoise and its practical applicability to clinical science with an emphasis on critical care and neurological research. We performed a review of educational material, review articles, methodological studies, and published clinical trials using the databases MEDLINE, PubMed, and ClinicalTrials.gov. The most relevant recommendations regarding design, conduction, and reporting of RCTs may include the following: 1) clinically relevant end points should be defined a priori, and an unbiased analysis and report of the study results should be warranted, 2) both significant and nonsignificant results should be objectively reported and published, 3) structured study design and performance as indicated in the Consolidated Standards of Reporting Trials statement should be employed as well as registration in a public trial database, 4) potential conflicts of interest and funding sources should be disclaimed in study report or publication, and 5) in the comparison of experimental treatment with standard care, preplanned interim analyses during an ongoing RCT can aid in maintaining clinical equipoise by assessing benefit, harm, or futility, thus allowing decision on continuation or termination of the trial.
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Spieth, Peter Markus, Anne Sophie Kubasch, Ana Isabel Penzlin, Ben Min-Woo Illigens, Kristian Barlinn, and Timo Siepmann. "Randomized controlled trials - a matter of design." Dove Medical Press, 2016. https://tud.qucosa.de/id/qucosa%3A29007.
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Randomized controlled trials (RCTs) are the hallmark of evidence-based medicine and form the basis for translating research data into clinical practice. This review summarizes commonly applied designs and quality indicators of RCTs to provide guidance in interpreting and critically evaluating clinical research data. It further reflects on the principle of equipoise and its practical applicability to clinical science with an emphasis on critical care and neurological research. We performed a review of educational material, review articles, methodological studies, and published clinical trials using the databases MEDLINE, PubMed, and ClinicalTrials.gov. The most relevant recommendations regarding design, conduction, and reporting of RCTs may include the following: 1) clinically relevant end points should be defined a priori, and an unbiased analysis and report of the study results should be warranted, 2) both significant and nonsignificant results should be objectively reported and published, 3) structured study design and performance as indicated in the Consolidated Standards of Reporting Trials statement should be employed as well as registration in a public trial database, 4) potential conflicts of interest and funding sources should be disclaimed in study report or publication, and 5) in the comparison of experimental treatment with standard care, preplanned interim analyses during an ongoing RCT can aid in maintaining clinical equipoise by assessing benefit, harm, or futility, thus allowing decision on continuation or termination of the trial.
4
VOLZ, TINA M. "DECISION MAKING REGARDING PARTICIPATION IN RANDOMIZED CONTROLLED TRIALS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1179517141.
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Kashyap, Sonya. "Assisted reproductive medicine: Systematic reviews and randomized controlled trials." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/26940.
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The objective for this thesis was to propose a question in the area of reproductive medicine that could be addressed by a clinical trial. In preparation for such a trial we conducted a systematic review of the topic.
Our first question was whether metformin is of benefit compared to clomiphene citrate for ovulation induction and achievement of pregnancy in women with polycystic ovarian syndrome (PCOS). We conducted a systematic review (SR) and meta-analysis of the subject before designing and implementing a randomized controlled trial (RCT). The RCT was terminated for recruitment issues. Our PCOS SR led us to develop a novel ovarian stimulation protocol for poor responders. We used the lessons learned from our failed RCT and another systematic review to design and conduct a feasibility randomized controlled trial on the use of aromatase inhibitors to improve pregnancy outcomes for in-vitro fertilization in poor responders. We successfully completed the pilot study and found a trend towards increased clinical pregnancy rates for patients who received the study versus the standard protocol. The pilot study provides recommendations for the definitive trial.
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Adjei, Seth Akonor. "Refining Prerequisite Skill Structure Graphs Using Randomized Controlled Trials." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/177.
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Prerequisite skill structure graphs represent the relationships between knowledge components. Prerequisite structure graphs also propose the order in which students in a given curriculum need to be taught specific knowledge components in order to assist them build on previous knowledge and improve achievement in those subject domains. The importance of accurate prerequisite skill structure graphs can therefore not be overemphasized. In view of this, many approaches have been employed by domain experts to design and implement these prerequisite structures. A number of data mining techniques have also been proposed to infer these knowledge structures from learner performance data. These methods have achieved varied degrees of success. Moreover, to the best of our knowledge, none of the methods have employed extensive randomized controlled trials to learn about prerequisite skill relationships among skills. In this dissertation, we motivate the need for using randomized controlled trials to refine prerequisite skill structure graphs. Additionally, we present PLACEments, an adaptive testing system that uses a prerequisite skill structure graph to identify gaps in students’ knowledge. Students with identified gaps are assisted with more practice assignments to ensure that the gaps are closed. PLACEments additionally allows for randomized controlled experiments to be performed on the underlying prerequisite skill structure graph for the purpose of refining the structure. We present some of the different experiment categories which are possible in PLACEments and report the results of one of these experiment categories. The ultimate goal is to inform domain experts and curriculum designers as they create policies that govern the sequencing and pacing of contents in learning domains whose content lend themselves to sequencing. By extension students and teachers who apply these policies benefit from the findings of these experiments.
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Yeung, Wing-fai, and 楊穎輝. "Acupuncture for insomnia: a systematic reviewand randomized placebo-controlled trials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43572157.
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Zhang, Li, Isola Ajiferuke, and Margaret Sampson. "Optimizing search strategies to identify randomized controlled trials in MEDLINE." BioMed Central, 2006. http://hdl.handle.net/10388/41.
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Background
The Cochrane Highly Sensitive Search Strategy (HSSS), which contains three phases, is widely used to identify Randomized Controlled Trials (RCTs) in MEDLINE. Lefebvre and Clarke suggest that reviewers might consider using four revisions of the HSSS. The objective of this study is to validate these four revisions: combining the free text terms volunteer, crossover, versus, and the Medical Subject Heading CROSS-OVER STUDIES with the top two phases of the HSSS, respectively.
Methods
We replicated the subject search for 61 Cochrane reviews. The included studies of each review that were indexed in MEDLINE were pooled together by review and then combined with the subject search and each of the four proposed search strategies, the top two phases of the HSSS, and all three phases of the HSSS. These retrievals were used to calculate the sensitivity and precision of each of the six search strategies for each review.
Results
Across the 61 reviews, the search term versus combined with the top two phases of the HSSS was able to find 3 more included studies than the top two phases of the HSSS alone, or in combination with any of the other proposed search terms, but at the expense of missing 56 relevant articles that would be found if all three phases of the HSSS were used. The estimated time needed to finish a review is 1086 hours for all three phases of the HSSS, 823 hours for the strategy versus, 818 hours for the first two phases of the HSSS or any of the other three proposed strategies.
Conclusion
This study shows that compared to the first two phases of the HSSS, adding the term versus to the top two phases of the HSSS balances the sensitivity and precision in the reviews studied here to some extent but the differences are very small. It is well known that missing relevant studies may result in bias in systematic reviews. Reviewers need to weigh the trade-offs when selecting the search strategies for identifying RCTs in MEDLINE.
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Zhao, Siyuan. "Towards Personalized Learning using Counterfactual Inference for Randomized Controlled Trials." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/189.
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Personalized learning considers that the causal effects of a studied learning intervention may differ for the individual student (e.g., maybe girls do better with video hints while boys do better with text hints). To evaluate a learning intervention inside ASSISTments, we run a randomized control trial (RCT) by randomly assigning students into either a control condition or a treatment condition. Making the inference about causal effects of studies interventions is a central problem. Counterfactual inference answers “What if� questions, such as "Would this particular student benefit more if the student were given the video hint instead of the text hint when the student cannot solve a problem?". Counterfactual prediction provides a way to estimate the individual treatment effects and helps us to assign the students to a learning intervention which leads to a better learning. A variant of Michael Jordan's "Residual Transfer Networks" was proposed for the counterfactual inference. The model first uses feed-forward neural networks to learn a balancing representation of students by minimizing the distance between the distributions of the control and the treated populations, and then adopts a residual block to estimate the individual treatment effect. Students in the RCT usually have done a number of problems prior to participating it. Each student has a sequence of actions (performance sequence). We proposed a pipeline to use the performance sequence to improve the performance of counterfactual inference. Since deep learning has achieved a huge amount of success in learning representations from raw logged data, student representations were learned by applying the sequence autoencoder to performance sequences. Then, incorporate these representations into the model for counterfactual inference. Empirical results showed that the representations learned from the sequence autoencoder improved the performance of counterfactual inference.
10
Torgerson, Carole. "Systematic reviews of randomized controlled trials in literacy research : methodological challenges." Thesis, University of Sheffield, 2006. http://etheses.whiterose.ac.uk/14638/.
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Introduction: In this item a 'tertiary' review of systematic reviews in literacy learning is presented. It explores the methodological quality of the identified systematic reviews and identifies the primary data that are used for the in-depth methodological work in Item 3 on the two main threats to the validity of systematic reviews: publication bias and design bias. Background: Recent governments in the UK have introduced a number of initiatives aimed at improving the literacy levels of children. It is important, therefore, that policy and practice are informed by the most rigorous available evidence, particularly for questions of effectiveness in literacy learning. It is also important that this evidence is subjected to rigorous critical scrutiny. Methods: Systematic reviews undertaken in the field of literacy learning in English in the years between 1983 and 2003 were searched for, located and quality assessed. The scope of the review was limited to systematic reviews of experimental research evaluating literacy interventions with quantifiable literacy outcome measures in English as a first (not second or additional) language and focusing on children and young people in school settings up to the age of 18. Results: A total of 14 systematic reviews containing meta-analyses and meeting all the inclusion criteria were included in the tertiary review. The following data were extracted from the reviews: literacy interventions, outcomes evaluated and effect sizes. The quality of the reviews was examined using an adaptation of the QUORUM statement. Overall the quality of the meta-analyses included in this tertiary review was good. When examining the effect sizes of randomized controlled trials (RCTs) and controlled trials (CTs) separately there was no clear pattern as to whether the RCTs produced a larger or smaller effect size than the CTs. Discussion: Overall the quality of the meta-analyses included in this tertiary review was good. The QUORUM checklist seemed to perform well for the appraisal of educational meta-analyses. All the reviews clearly stated their research question, and their methods of searching for and selecting included studies. Most studies described their data extraction and used some form of quality assessment of included studies. On the other hand, some reviews did have notable methodological weaknesses. Six of the 14 studies did not make an assessment of publication bias, which is potentially a major threat to the validity of any systematic review. In addition, six studies did not provide evidence for reviewer agreement when synthesising the data. There is, therefore, some room for improvement in the methodological quality of systematic reviews in literacy learning. Conclusions: A number of reviews in this tertiary review are judged to be of sufficiently high quality to provide reliable evidence for the effectiveness of literacy interventions.
11
Hayasaka, Yu. "Dose equivalents of antidepressants: Evidence-based recommendations from randomized controlled trials." Kyoto University, 2016. http://hdl.handle.net/2433/215444.
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http://dx.doi.org/10.1016/j.jad.2015.03.021Kyoto University (京都大学)
0048
新制・課程博士
博士(医学)
甲第19618号
医博第4125号
新制||医||1015(附属図書館)
32654
京都大学大学院医学研究科医学専攻
(主査)教授 川上 浩司, 教授 清水 章, 教授 村井 俊哉
学位規則第4条第1項該当
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Yeung, Wing-fai. "Acupuncture for insomnia a systematic review and randomized placebo-controlled trials /." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43572157.
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Braun, Thomas Michael. "Optimal analysis of group randomized trials with permutation tests /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/9589.
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Dunning, Andrew J. "Aspects of matching and power in group randomized trials /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/9592.
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You, Zhiying. "Power and sample size of cluster randomized trials." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/you.pdf.
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Shea, Beverley Julia. "Assessing the quality of reporting in meta-analyses of randomized controlled trials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/MQ46609.pdf.
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Stanev, Roger. "The epistemology and ethics of early stopping decisions in randomized controlled trials." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42539.
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Philosophers subscribing to particular principles of statistical inference and evidence need to be aware of the limitations and practical consequences of the statistical approach they endorse. The framework proposed (for statistical inference in the field of medicine) allows disparate statistical approaches to emerge in their appropriate context. My dissertation proposes a decision theoretic model, together with methodological guidelines, that provide important considerations for deciding on clinical trial conduct. These considerations do not amount to more stopping rules. Instead, they are principles that address the complexity of interpreting and responding to interim data, based on a broad range of epistemic and ethical factors. While they are not stopping rules, they would assist a Data Monitoring Committee in judging its position with regard to necessary precautionary interpretation of interim data. By vindicating a framework that accommodates a wide range of approaches to statistical inference in one important setting (clinical trials), my results pose a serious challenge for any approach that advocates a single, universal principle of statistical inference.
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Romano, Jennifer A. Z. "Reliability and Validity Practices in Randomized Controlled Trials: Current Trends and Recommendations." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/9142.
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The verity of conclusions drawn from psychological research hinges on the reliability and validity of the measures used to collect the data. Any research conducted using measures with low reliability or validity is rendered essentially useless; thus, reporting reliability and validity evidence for measures employed in research is an essential component in creating rigorous, replicable research. Multiple reporting standards have been implemented and revised over the years with the intent to improve measurement and reporting practices within clinical psychology, though few guidelines have been suggested regarding adequate reporting practices for studies' measures. We reviewed a representative sample of randomized clinical trials (RCTs) published in the Journal of Clinical and Counseling Psychology in 1994, 2002, 2010, and 2018 for reported reliability and validity evidence. We examined whether the implementation of reporting standards led to improvement in reporting measures' reliability and validity evidence over time, along with how frequently articles recently published in one of the top clinical psychology journals reported reliability and validity evidence. We found that only 58.1% of measures used in articles published in 2018 reported reliability evidence, and only 12.4% reported validity evidence. Furthermore, although reporting of reliability and validity evidence has improved when comparing articles published in 2018 to those published in 1994 or 2002, such reporting practices were not significantly different from articles published in 2010. We provide a discussion of the importance of these findings and recommendations for improving reporting practices in future research.
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Craft, Emalee, and Rachel Ogumbo. "Use of CONSORT Criteria for Reporting Randomized Controlled Trials in Pharmacy Journals." The University of Arizona, 2012. http://hdl.handle.net/10150/623596.
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Class of 2012 AbstractSpecific Aims: To explore whether publishing requirements for human-centered randomized control trials, particularly the CONSORT criteria, have any relationship to impact as measured by the Journal Citation Reports TM Impact Factor. Methods: A worksheet was used to evaluate a methodically selected list of journals, including types of articles published, requirements of authors for human-focused randomized control trials, JCR Impact Factor and other JCR metrics for each specific journal title. A worksheet was filled out for each journal by each member of the research team and answers combined for consensus. Group means and SDs were calculated and the Student’s t-Test applied to values for selected journals. Main Results: 50 candidate pharmacy journals were identified and 41 met the criteria for publishing human-centered randomized control trials. Journals were grouped according to whether they required CONSORT or had other reporting requirements for human RCTs, or had no requirements for such studies. Few (6; 15%) pharmacy journals required authors to use CONSORT; and additional 15 (37%) journals provided as least some author guidelines similar to CONSORT. Pharmacy journals using CONSORT or other guidelines had a higher average impact factor (3.5; SD = 1.5) than did journals without guidelines (2.4; SD = 0.9; p = 0.007). Conclusions: There appears to be a statistical difference in average JCR metrics between journals which require specific RCT guidelines and those which do not. The use of reporting guidelines, such as CONSORT, by pharmacy journals is associated with increased impact as represented by JCR influence measures.
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Craft, Emalee, Rachel Ogumbo, and Marion Slack. "Use of CONSORT Criteria for Reporting Randomized Controlled Trials in Pharmacy Journals." The University of Arizona, 2012. http://hdl.handle.net/10150/614462.
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Class of 2012 AbstractSpecific Aims: To explore whether publishing requirements for human-centered randomized control trials, particularly the CONSORT criteria, have any relationship to impact as measured by the Journal Citation Reports ™ Impact Factor. Methods: A worksheet was used to evaluate a methodically selected list of journals, including types of articles published, requirements of authors for human-focused randomized control trials, JCR Impact Factor and other JCR metrics for each specific journal title. A worksheet was filled out for each journal by each member of the research team and answers combined for consensus. Group means and SDs were calculated and the Student’s t-Test applied to values for selected journals. Main Results: 50 candidate pharmacy journals were identified and 41 met the criteria for publishing human-centered randomized control trials. Journals were grouped according to whether they required CONSORT or had other reporting requirements for human RCTs, or had no requirements for such studies. Few (6; 15%) pharmacy journals required authors to use CONSORT; and additional 15 (37%) journals provided as least some author guidelines similar to CONSORT. Pharmacy journals using CONSORT or other guidelines had a higher average impact factor (3.5; SD = 1.5) than did journals without guidelines (2.4; SD = 0.9; p = 0.007). Conclusions: There appears to be a statistical difference in average JCR metrics between journals which require specific RCT guidelines and those which do not. The use of reporting guidelines, such as CONSORT, by pharmacy journals is associated with increased impact as represented by JCR influence measures.
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Chong, Shing-kan Patrick. "A randomized controlled trial for exercise prescription in general practice." Click to view the E-thesis via HKUTO, 2003. http://sunzi.lib.hku.hk/hkuto/record/B31970977.
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Shi, Shitian, and 石诗田. "Physical activity and anxiety in adolescents : a systematic review of randomized controlled trials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206985.
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Background
Anxiety disorders are among the most prevalent psychological disorders experienced during adolescence. Studies have suggested that physical activity may contribute to a beneficial role for anxiety including the prevention and reduction of anxiety symptoms among adolescents. This systematic review aims to explore the possible relationship between physical activity and anxiety.
Methods
A systematic search was performed to locate randomized-controlled trials (RCT)from 1980to 30 April 2014 in PubMed, MEDLINE(ProQuest), PsycINFO(ProQuest) and Google scholar. Quality of RCTs was assessed using JADAD. The relationship of physical activity and anxiety was explored. The change of anxiety reported scores for intervention groups in the follow-up period was tabulated.
Findings
From the results of five studies, physical activity may change mean anxiety scores in the general population of adolescents respectively. Regarding the within intervention group analysis, five studies had showed the significant changes compared pre-test and post-test anxiety scores, which support the positive effects of physical activity on anxiety. But no more evidence showed the specific period and depth the effects of interventions group as seldom trials reported follow-up data. That meant, we couldn’t tell whether there was enduring impacts of physical activity on reduction of anxiety symptoms. In these studies, the evidence of improvement levels of physical activity was weak as there were no consistent criteria of vigorous and aerobic exercise.
Conclusion
The reduction of anxiety scores with physical activity intervention is the main findings. Though most results showed significant improvement, limitations in the study design, analysis and reporting limit the inferences regarding the effect of physical activity on the reduction and prevention of anxiety.published_or_final_version
Public Health
Master
Master of Public Health
23
Dong, Ranran. "Stepped Wedge Cluster Randomized Controlled Trials for Three-Level Data: Design and Evaluation." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514492341281384.
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Siegfried, Nandi Louise. "Methodological quality of randomized controlled trials of HIV/AIDS interventions, with special reference to trials conducted in Africa." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436962.
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Reichmann, William Michael. "Methods in subgroup analysis: estimation of risk and implications for randomized controlled trial design." Thesis, Boston University, 2012. https://hdl.handle.net/2144/32047.
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Thesis (Ph.D.)--Boston UniversityPLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
Estimation of exposure-specific risks (ESRs) using estimates of the overall risk and relative risk of disease given exposure has been performed in previous studies, but the performance of such an estimator has not been assessed nor has a variance for such an estimate been proposed. In this project I evaluated the performance of a simple product-based ESR and its variance derived using the delta method. I used the variance to estimate the 95% confidence interval. I found that this point estimate was biased and that the accompanying 95% confidence interval did not attain 95% coverage. I also proposed a revised product-based estimator and found that this estimator was unbiased. I used the delta method to derive a variance for this estimator and estimated the 95% confidence interval. The coverage of this interval attained 95% coverage in most situations. According to the CONSORT statement, subgroup analyses in randomized controlled trials (RCTs) should be pre-planned and accompanied with a formal test of interaction. I considered the interaction between treatment and a dichotomous prognostic factor with a continuous outcome. I examined the impact of misspecifying the distribution of the prognostic factor on power and sample size for interaction effects. I found that power for the interaction test was decreased when the misspecification of the distribution of the prognostic factor was away from a balanced design. I also proposed three methods for improving the power under misspecifications. Quota sampling maintained the power at 80%, but trial completion may be delayed under misspecifications. Modified quota sampling improved the power, but results were related to the proportion of trials switching to the quota sampling procedure. Sample size re-estimation improved the power, but did not always attain 80% power. All three methods maintained appropriate type I error. Lastly, I examined the impact of unplanned cross-over on power and sample size for interaction effects in RCTs. Unplanned cross-over is common in surgical trials and can diminish the magnitude of the interaction effect. Due to this, the sample size re-estimation procedure performed better than quota sampling and modified quota sampling in the presence of unplanned cross-over.
2031-01-02
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Chong, Shing-kan Patrick, and 莊承謹. "A randomized controlled trial for exercise prescription in general practice." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31970977.
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Shepherd, Bryan E. "Causal inference in HIV vaccine trials : comparing outcomes in a subset chosen after randomization /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/9608.
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Sjögren, Petteri. "Randomised clinical trials and evidence-based general dentistry /." Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/med865s.pdf.
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Li, Yifang, and 李怡芳. "Effectiveness of telemedicine applications for weight management : a meta-analysis of randomized controlled trials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206938.
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Background
The telemedicine application has great potential to address the prevalence of overweight and obesity, a severe the public healthcare burden in the 21st century. However, no exiting systematic review has been investigated the effectiveness of telemedicine application of weight reduction. The absence of quantitative evaluations and relatively rigorous qualitative assessments explains the carry-out of the present systematic review with a meta-analysis.
Objectives
The objectives are to determine the aggregated effect of thetelemedicine application to the management of overweight and obesity, in particular to investigate the effect of thetelemedicine application on reducing body weight, and to evaluate major contributable factors to commit a successful telemedicine intervention in body weight lowering.
Methods
This meta-analysis is guided by the PRISMA statement, with the automatic and manual searching by input keywords in the main databases. Only RCTs with absolute reduction of body weight as outcome measure, comparing the effect of the telemedicine application interventions with other stated interventions in reducing human body weightare potentially to be included. The selected RCTs are subject to the Jaded scale and the CONSORT for quality assessment. The studies identification and the data extraction were performed by two independent reviewers separately.The heterogeneity across the selected RCTs was assessed by Cochran Q test and I-square statistic. The meta-analysis was conducted with random-effect models and sensitivity analyses were performed by eliminating studies with extreme outcome values. Publication bias was examined through visual inspection of funnel plots and statistical assessments of the Begg‟s rank correlation test and the fail-safe N.
Results
723 studies were identified from the preliminary database searches, 32 full-text articles were retrieved to review, after which, 12 RCTs were subject to the quality assessment process. Only 10 RCTs of high quality were selected into the meta-analysis. The generalizability of the meta-analysis is great since the patients subgroups were broadly from different geographical and cultural settings with the age ranging from 18 to 70, and no comorbidity conditions were excluded. The single element, the telemedicine application intervention, contributed to a significant extra 4.17 kg absolute reduction of human body weight in the average time period of 42 weeks. The outcome of the sensitivity analysis excluding the studies with extreme outcome measures was also consistent with the finding, which means the telemedicine application intervention contributed to a significant extra 2.58 kg absolute reduction of human body weight in the average time period of 46.5 weeks.
Conclusions
The telemedicine application is an effective public health intervention with broad generalizability for weight reduction in the future. Further studies to assess the effect of the telemedicine intervention among the populations of the developing countries, especially the large Chinese population, and to evaluate the confounding effect of the Hawthorne effect are critically important to support the international guideline on the promotion of the telemedicine intervention.published_or_final_version
Public Health
Master
Master of Public Health
30
Beath, Andrew. "Randomized Institutional Isomorphism - Evidence from Afghanistan." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10395.
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The dissertation compiles a series of essays which describes effects of various institutional variations randomized across a sample of 500 villages in Afghanistan in 2007. The first essay examines the institutional effects of the creation of democratically-elected, gender-balanced village development councils across 474 village councils. The creation of councils is found to have no effects on the structure and function of local governance or on how male villagers perceive local governance quality. However, council creation provokes increased local governance activity among paramilitary commanders – who experience broad-based improvements in public perceptions – and improves perceptions of local governance quality among women. The results indicate that externally-imposed de jure reforms do not substantially alter institutional outcomes, but may provoke countervailing responses by political authorities seeking to benefit from the institutional change. The second essay examines the effects of direct democracy on the alignment between public resource allocation decisions and citizen preferences. Using data from 250 villages, the study compares decision outcomes produced by secret-ballot referenda with outcomes produced by public meetings led by an elected village council. The results indicate that while elites do exert influence over outcomes produced by public meetings, their preferences do not determine the outcomes of referenda, which are influenced primarily by citizen preferences. Referenda are also found to improve citizen satisfaction, which is particularly low where elites exert undue influence over outcomes. The third essay examines whether the inclusion of villages in Afghanistan‘s largest development program affects counter-insurgency outcomes, such as individual perceptions of well-being, attitudes towards government, and the occurrence of violent incidents in surrounding areas. The program is found to affect all three measures, but only in areas with low levels of initial violence. The results indicate that development programs can limit the onset of insurgencies in relatively secure areas, but are not effective in improving attitudes to government and reducing violence where insurgents are already active.Government
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Weir, Arielle. "Conducting Cluster Randomized Controlled Trials in Hospitals: Barriers and Enablers Assessment and Strategies to Facilitate Delivery." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41509.
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Background: Cluster randomized control trials (cRCTs) are useful for asking about system-level interventions compared to other types of clinical research design, however they present unique challenges with conduct and delivery. Numerous cRCTs in hospitals have encountered challenges and time delays in enrolling hospitals and launching the trials which contributes to research waste. While each cRCT has unique barriers and enablers to their conduct, it is important to understand and explore these factors at the general level of the cRCT itself. Previous literature has documented factors associated with successful cRCTs, however, these studies focused primarily on the statistical aspect, while neglecting to evaluate the delivery of the trial.
Objectives: The goal of this dissertation was to explore barriers and enablers to conducting cRCTs in hospitals, and to identify potential strategies that facilitate their delivery. This research was conducted to identify evidence and generate guidance for researchers aiming to conduct these trials. Specifically, the objectives were: 1) To explore the current knowledge and evidence surrounding the implementation of cRCTs in hospitals; 2) To explore from the perspective of the coordinating site, what influenced the delivery and hospital engagement of an ongoing cRCT, and what challenges were encountered; 3) To identify strategies to facilitate delivery of cRCTs in hospitals; 4) To systematically review reported recruitment strategies of healthcare facilities in cRCTs.
Methods: The dissertation employed multiple research methods. To address the first objective, a scoping review was performed of current literature related to hospitals in cRCTs. The second objective was addressed with a qualitative case study. Semi-structured interviews were carried out with six key members of the team to understand their perceptions of the delivery of the trial. For the third objective, a tool matching two implementation concepts (the Consolidated Framework for Implementation Research (CFIR)- Expert Recommendations for Implementing Change (ERIC) matching tool) was used to identify strategies targeted to address barriers and enablers to cRCT conduct identified in the first two studies. Lastly, a systematic review was performed to address the fourth objective, to identify reported strategies used for hospital engagement in cRCTs. The thesis was guided and analyzed using an over-arching implementation framework, CFIR, and an implementation strategies list, the ERIC compilation. This was done to allow comparability and synthesis of results between methodologies from the dissertation, and between the results from the studies and previous literature. Results: Several key CFIR domains were identified in the literature in the scoping review that were determined to being influential for conducting the cRCTs in hospitals: the adaptability to tailor the trial to each site; the engagement of opinion leaders, champions and formally appointed implementation leaders in the cRCT process as facilitators to conducting the trial; the lack of a site perceiving a relative priority for the trial or tension for change for the clinical field presenting barriers to conducting the cRCT; and limited available resources can present barriers to conducting the cRCT. The qualitative case study identified similar CFIR domains and constructs as potentially influential for cRCT conduct, including the emphasis on adaptability of trial, the importance of tension for change in the sites for accepting inclusion in the trial, the availability of resources, and the engagement of leaders. The CFIR-ERIC matching study identified strategies that may be used to overcome barriers and target enablers for cRCT delivery from CFIR domains and constructs identified in the first two studies. A list of strategies was generated, ranked by the number of many determinants for which the strategy was listed as a Level 1 strategy, then by how many determinants for which the strategy was listed as a Level 2 strategy. The top ERIC strategies that were endorsed as a Level 1 strategy for any or multiple CFIR domains were: 1) Identify and prepare champions, 2) Conduct local needs assessment, 3) Conduct educational meetings, 4) Inform local opinion leaders, 5) Build a coalition, 6) Promote adaptability, 7) Develop a formal implementation blueprint, 8) Involve patients/consumers and family members, 9) Obtain and use patients/consumers and family feedback, 10) Develop educational materials, 11) Promote network weaving, 12) Distribute educational materials, 13) Access new funding, and 14) Develop academic partnerships. The systematic review identified literature reporting on the recruitment of healthcare facility sites into cRCTs. Numerous strategies for cRCT site recruitment were identified, and these were coded to the ERIC compilation. Strategies that were commonly cited were: involve executive boards, promote network weaving, conduct educational meetings, inform local opinion leaders, and centralize technical assistance.
Conclusions: The results from the dissertation can contribute to the knowledge for facilitating cRCT delivery in hospitals while recognizing the critical limitations in the studies. Key concepts and strategies to facilitate the conduct and delivery of cRCTs in hospitals were identified. Future research should aim to empirically evaluate the identified strategies. Researchers should aim to address the reporting gap for cRCT delivery identified by this dissertation.
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Taylor, Leslie. "Estimating causal treatment effect in randomized clinical trials with noncompliance and outcome nonresponse /." Thesis, Connect to this title online; UW restricted, 2008. http://hdl.handle.net/1773/9601.
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Ward, Roxanne E. "Examining Methods and Practices of Source Data Verification in Canadian Critical Care Randomized Controlled Trials." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23974.
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Statement of the Problem: Source data verification (SDV) is the process of comparing data collected at the source to data recorded on a Case Report Form, either paper or electronic (1) to ensure that the data are complete, accurate and verifiable. Good Clinical Practice (GCP) Guidelines are vague and lack evidence as to the degree of SDV and whether or not SDV affects study outcomes.
Methods of Investigation: We performed systematic reviews to establish the published evidence-base for methods of SDV and to examine the effect of SDV on study outcomes. We then conducted a national survey of Canadian Critical Care investigators and research coordinators regarding their attitudes and beliefs regarding SDV. We followed by an audit of the completed and in-progress Randomized Controlled Trials (RCTs) of the Canadian Critical Care Trials Group (CCCTG).
Results: Systematic Review of Methods of SDV: The most common reported or recommended frequency of source data verification (10/14 - 71%) was either based on level or risk, or that it be conducted early (i.e. after 1st patient enrolled). The amount of SDV recommended or reported, varied from 5-100%. Systematic Review of Impact of SDV on Study Outcomes: There was no difference in study outcomes for 1 trial and unable to assess in the other. National Survey of Critical Care Investigators and Research Coordinators: Data from the survey found that 95.8% (115/120) of respondents believed that SDV was an important part of Quality Assurance; 73.3% (88/120) felt that academic studies should do more SDV; and 62.5% (75/120) felt that there is insufficient funding available for SDV. Audit of Source Data Verification Practices in CCCTG RCTs: In the national audit of in-progress and completed CCCTG RCTs, 9/15 (60%) included a plan for SDV and 8/15 (53%) actually conducted SDV. Of the 9 completed published trials, 44% (4/9) conducted SDV.
Conclusion: There is little evidence base for methods and effect of SDV on study outcomes. Based on the results of the systematic review, survey, and audit, more research is needed to support the evidence base for the methods and effect of SDV on study outcomes.
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Diaz, Alison. "Yoga as a treatment for low back pain a systematic review of randomized controlled trials." Honors in the Major Thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/372.
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Background: Low back pain is very common and has a tremendous economic impact. With the prevalence and incidence of low back pain on the rise, individuals are turning to alternative treatments. Yoga is the most widely used complementary and alternative medicine treatment for low back pain and it is not fully certain how effective this method is for resolving the symptoms. Objectives: The purpose of this manuscript is to systematically review the current literature for randomized controlled trials that assess the outcomes of yoga intervention in individuals with low back pain. Methods: An electronic database search was performed to analyze studies. To be included in the review, the studies were required to be a randomized controlled trial, published in English, present in a peer reviewed journal, identify yoga as the primary treatment focus for low back pain in at least one group, and included participants with at least a 12 week history of low back pain. Results: A search of the databases revealed 177 articles, of which, 8 met the inclusion criteria. Conclusions: Yoga intervention appears to be effective in alleviating symptoms brought on by low back pain. Yoga was either demonstrated to significantly improve quality of life and reduce disability, stress, depression, and medication usage associated with low back pain in 6 of the 8 analyzed trials. More research is necessary to account for the lack of between-group differences in two trials.B.S.
Bachelors
Health and Public Affairs
Health Sciences; Pre-Clinical
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Windrim, Rory. "A randomized controlled trial of oral Misoprostol in the induction of labour at term /." St. John's, NF : [s.n.], 1999.
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Balbach, Ulrike Margarethe. "Stability change of chemically modified SLA titanium palatal implants : a randomized controlled clinical trial /." [S.l.] : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000278510.
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Fergusson, Nicholas Anthony. "Alternative Endpoints and Analysis Techniques in Kidney Transplant Trials." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36230.
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Clinical trials in kidney transplantation suffer from several major issues including:
1) Unfeasibility due to low short-term event rates of hard outcomes and 2) Reliance on a composite outcome that consists of unequal endpoints that may generate misleading results. This thesis attempts to explore and apply methods to solve these issues and ultimately, improve kidney transplantation trials.
We present a secondary analysis of the ACE trial in kidney transplant using composites with alternative graft function surrogate endpoints. Typically, kidney transplant trials—including the ACE trial— use a time-to-event composite of death, end-stage renal disease (ESRD), and doubling of serum creatinine. Instead of doubling of serum creatinine, we investigated the use of percentage declines of estimate glomerular filtration rate (eGFR) within a time-to-event composite of death and ESRD. Additionally, we present an application of an innovative analysis method, the win ratio approach, to the ACE trial as a way of lessening concerns associated with unequal composite endpoints.
Composites of death, ESRD, and either a 40%, 30% or 20% decline in eGFR did not alter original ACE trial results, interpretations, or conclusions. The win ratio approach, and the presentation of a win ratio, generated very comparable results to a standard time-to-event analysis while lessening the impact of unequal composite endpoints and making fewer statistical assumptions. This research provides a novel, trial-level application of alternative endpoints and analysis techniques within a kidney transplant trial setting.
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Bucci, Jay Robert. "A statistical method for detection of small-study effects in meta-analyses of randomized controlled trials." Thesis, The University of Texas Health Science Center at San Antonio, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10137622.
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Small-study effects, which are factors resulting in dependencies between treatment effect size and precision, are an important source of bias in meta-analyses of randomized controlled trials. However, established nonparametric tests for detection of small-study effects that are based on rank correlation lack statistical power, while established parametric tests that are based on linear regression are not robust in the presence of between-study heterogeneity.
A novel method for detection of small-study effects is proposed that is designed to overcome these limitations. The method uses repeated one-sample Wald-Wolfowitz runs tests to evaluate the null hypothesis of serial independence among trial treatment effect size estimates that are ranked by precision. This dissertation describes lower-tailed, upper-tailed, and two-tailed versions of the proposed method for detection of small-study effects and compares the proposed method to established tests using simulation. The novel method is implemented in Stata using various procedures for control of type 1 error, including the Bonferroni and Sidak corrections, Hochberg’s step-up procedure, and the Benjamini-Hochberg procedure for control of the false discovery rate. The type 1 error rate and power of the novel method are then compared to those of existing tests, including the nonparametric rank correlation test of Begg and Mazumdar and the commonly-used regression-based tests of Egger, Harbord, and Peters. Factors known to affect the performance of established tests, including effect size, number of trials in each meta-analysis, degree of between-study heterogeneity, and degree and type of publication bias (a specific cause of small-study effects) are simulated to reflect characteristics of meta-analyses in the biomedical literature.
The simulation demonstrated that all of the procedures evaluated for control of type 1 error in the novel method maintained an error rate below the nominal rate under all scenarios, suggesting that any of these procedures may be used to implement the novel method. In contrast, error rates for the established tests of Begg and Mazumdar, Egger, Harbord, and Peters were at or above the nominal rate under most scenarios. The lower-tailed, upper-tailed, and two-tailed novel tests showed little power in excess of the type 1 error rate under all conditions. In contrast, established tests demonstrated variable power depending on the conditions. Specifically, the power of established tests increased with an increase in effect size, an increase in the number of trials in each meta-analysis, an increase in the severity of publication bias, and publication bias that operated by effect size rather than by p-value. In contrast, the power of established tests decreased with an increase in heterogeneity. Overall, Egger’s test demonstrated the highest power. Despite the low power of the novel method, selected circumstances under which it may be useful are described.
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Pasupuleti, Vinay, Angel Arturo Escobedo, Abhishek Deshpande, Priyaleela Thota, Yuani Roman, and Adrian V. Hernández. "Efficacy of 5-Nitroimidazoles for the Treatment of Giardiasis: A Systematic Review of Randomized Controlled Trials." Public Library of Science (PLoS), 2014. http://hdl.handle.net/10757/316481.
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Background: Giardiasis is one of the most common causes of diarrheal disease worldwide and 5-nitroimidazoles (5-NI) are
the most commonly prescribed drugs for the treatment of giardiasis. We evaluated the efficacy of 5-nitroimidazoles (5-NI) in
the treatment of giardiasis in a systematic review of randomized controlled trials (RCTs).
Methodology/Principal Findings: We conducted a comprehensive literature search in PubMed-Medline, Scopus, Web of
Science and Cochrane Library for RCTs evaluating the efficacy of 5-NI vs. control (placebo or active treatment) on
parasitological cure in patients with parasitologically-demonstrated giardiasis. The search was performed in May 2013 with
no language restriction by two authors independently. The efficacy outcome was parasitological cure, and harmful
outcomes were abdominal pain, bitter or metallic taste, and headache. We included 30 RCTs (n = 3,930). There was a
significant and slightly higher response rate with 5-NI in giardiasis treatment (RR 1.06, 95%CI 1.02–1.11, p = 0.005). There was
high heterogeneity among studies (I2= 72%). The response rates for metronidazole, tinidazole and secnidazole were similar
(RR 1.05, 95%CI 1.01–1.09, p = 0.01; RR 1.32 95%CI 1.10–1.59, p = 0.003; and RR 1.18 95%CI 0.93–1.449, p = 0.18, respectively).
On subgroup analyses, the response rates did not vary substantially and high heterogeneity persisted (I2= 57%–80%).
Harmful outcomes were uncommon, and 5-NIs were associated with lower risk of abdominal pain, and higher risk of both
bitter or metallic taste and headache.
Conclusions: Studies investigating the efficacy of 5-NI in giardiasis treatment are highly heterogeneous. 5-NIs have a slightly
better efficacy and worse profile for mild harmful outcomes in the treatment of giardiasis in comparison to controls. Larger
high quality RCTs are needed to further assess efficacy and safety profiles of 5-NI.
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Wang, Yan. "Student Modeling From Different Aspects." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/205.
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With the wide usage of online tutoring systems, researchers become interested in mining data from logged files of these systems, so as to get better understanding of students. Varieties of aspects of students’ learning have become focus of studies, such as modeling students’ mastery status and affects. On the other hand, Randomized Controlled Trial (RCT), which is an unbiased method for getting insights of education, finds its way in Intelligent Tutoring System. Firstly, people are curious about what kind of settings would work better. Secondly, such a tutoring system, with lots of students and teachers using it, provides an opportunity for building a RCT infrastructure underlying the system. With the increasing interest in Data mining and RCTs, the thesis focuses on these two aspects. In the first part, we focus on analyzing and mining data from ASSISTments, an online tutoring system run by a team in Worcester Polytechnic Institute. Through the data, we try to answer several questions from different aspects of students learning. The first question we try to answer is what matters more to student modeling, skill information or student information. The second question is whether it is necessary to model students’ learning at different opportunity count. The third question is about the benefits of using partial credit, rather than binary credit as measurement of students’ learning in RCTs. The fourth question focuses on the amount that students spent Wheel Spinning in the tutoring system. The fifth questions studies the tradeoff between the mastery threshold and the time spent in the tutoring system. By answering the five questions, we both propose machine learning methodology that can be applied in educational data mining, and present findings from analyzing and mining the data. In the second part, we focused on RCTs within ASSISTments. Firstly, we looked at a pilot study of reassessment and relearning, which suggested a better system setting to improve students’ robust learning. Secondly, we proposed the idea to build an infrastructure of learning within ASSISTments, which provides the opportunities to improve the whole educational environment.
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Bill-Axelson, Anna. "Localized Prostate Cancer : Results From a Randomized Clinical Trial." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5737.
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Osanai, Toshiya, Vinay Pasupuleti, Abhishek Deshpande, Priyaleela Thota, Yuani Roman, Adrian V. Hernández, and Ken Uchino. "Acute Endovascular Reperfusion Therapy in Ischemic Stroke: A Systematic Review and Meta-Analysis of Randomized Controlled Trials." The Public Library of Science (PLOS), 2015. http://hdl.handle.net/10757/552402.
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uchinok@ccf.orgBackground Randomized controlled trials (RCTs) of endovascular therapy for acute ischemic stroke have had inconsistent results. We evaluated the efficacy and safety of endovascular therapy in published RCTs. Methods We performed a systematic review of RCTs of endovascular therapy with thrombolytic or mechanical reperfusion compared with interventions without endovascular therapy. Primary outcome was the frequency of good functional outcome (modified Rankin scale (mRS) of 0-2 at 90 days) and secondary outcomes were mortality at 90 days and symptomatic intracranial hemorrhage (sICH). Random-effects meta-analysis was performed and the Cochrane risk of bias assessment was used to evaluate quality of evidence. Results Ten studies involving 1,612 subjects were included. Endovascular therapy was not significantly associated with good functional outcome (Relative Risk [RR] =1.17; 95% CI, 0.97 to 1.42; p=0.10 and Absolute Risk Difference [ARD] =7%; 95%CI -0.1% to 14%; p=0.05); heterogeneity was moderate among studies (I2=30%). Mortality was unchanged with endovascular therapy (RR=0.92; 95 % CI, 0.75 to 1.13; p=0.45) and there was no difference in sICH (RR=1.20; 95 % CI, 0.79 to 1.82; p=0.39). The quality of evidence was low for all outcomes and the recommendation is weak for the use of endovascular therapy as per GRADE methodology. Conclusions Intra-arterial therapy did not show significant increase in good outcomes and no changes in either mortality or sICH in patients with acute ischemic stroke. We need further RCTs with better design and quality to evaluate the true efficacy of endovascular therapy.
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Mukaka, Mavuto. "Comparison of statistical methods of handling missing binary outcome data in randomized controlled trials of efficacy studies." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/14593/.
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The presence of some missing outcomes in randomized studies often complicates the estimation of measures of effect, even in well designed randomized controlled trials. The process may be complicated further when the efficacy rates are close to 0% or 100% as the standard binomial model is susceptible to model non-convergence. The main objective of this study was to compare the performance of multiple imputation (MI) and Complete Case analysis for dealing with missing binary outcomes when modeling a risk difference. Firstly, however, the binomial regression COPY method and the Cheung’s modified Ordinary Least Squares (OLS) method were examined using simulation processes for their appropriateness in risk difference modeling. It was found that the number of copies (for the COPY method) required to minimize non-convergence coincided with the number of copies that gave the most biased estimates of the true efficacy difference while increasing the number of copies made the problems of non-convergence and bias worse; using Cheung’s method, however, there was 100% convergence with unbiased estimates of effect size. Simulation methods were used to compare the performance of complete case (CC) analysis and several multiple imputation (MI) models for handling missing outcome data over a wide range of efficacy environments and missing value assumptions. When outcomes were missing at random (MAR) or completely at random (MCAR), MI analyses that included treatment group membership in the imputation calculations yielded unbiased estimates of efficacy differences. The CC method was found to be as good, and often better, than MI methods when outcomes were MAR or MCAR, with coverage close to 95% in many situations – but neither CC nor MI produced unbiased estimates of effect difference when outcomes were missing not at random (MNAR). It was concluded that CC and MI methods are equally good in terms of producing unbiased estimates of effect difference in most missing outcome situations, but applying the intention to treat principle (ITT) which requires all randomized patients to be included in the primary analysis of a RCT, MI should be adopted as the analysis method of first choice, accompanied by a secondary CC analysis for sensitivity purposes (i.e. to investigate the extent of any likely bias).
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Bell, Melanie L., Amy L. Whitehead, and Steven A. Julious. "Guidance for using pilot studies to inform the design of intervention trials with continuous outcomes." DOVE MEDICAL PRESS LTD, 2018. http://hdl.handle.net/10150/627081.
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Background: A pilot study can be an important step in the assessment of an intervention by providing information to design the future definitive trial. Pilot studies can be used to estimate the recruitment and retention rates and population variance and to provide preliminary evidence of efficacy potential. However, estimation is poor because pilot studies are small, so sensitivity analyses for the main trial's sample size calculations should be undertaken. Methods: We demonstrate how to carry out easy-to-perform sensitivity analysis for designing trials based on pilot data using an example. Furthermore, we introduce rules of thumb for the size of the pilot study so that the overall sample size, for both pilot and main trials, is minimized. Results: The example illustrates how sample size estimates for the main trial can alter dramatically by plausibly varying assumptions. Required sample size for 90% power varied from 392 to 692 depending on assumptions. Some scenarios were not feasible based on the pilot study recruitment and retention rates. Conclusion: Pilot studies can be used to help design the main trial, but caution should be exercised. We recommend the use of sensitivity analyses to assess the robustness of the design assumptions for a main trial.
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Dinca, Madalina, Maria-Corina Serban, Amirhossein Sahebkar, Dimitri P. Mikhailidis, Peter P. Toth, Seth S. Martin, Michael J. Blaha, et al. "Does vitamin D supplementation alter plasma adipokines concentrations? A systematic review and meta-analysis of randomized controlled trials." Elsevier B.V, 2016. http://hdl.handle.net/10757/605887.
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We aimed to elucidate the role of vitamin D supplementation on adipokines through a systematic review and a meta-analysis of randomized placebo-controlled trials (RCTs). The search included PUBMED, Scopus, Web of Science and Google Scholar through July 1st, 2015. Finally we identified 9 RCTs and 484 participants. Meta-analysis of data from 7 studies did not find a significant change in plasma adiponectin concentrations following vitamin D supplementation (mean difference [MD]: 4.45%, 95%CI: -3.04, 11.93, p=0.244; Q=2.18, I(2)=0%). In meta-regression, changes in plasma adiponectin concentrations following vitamin D supplementation were found to be independent of treatment duration (slope: 0.25; 95%CI: -0.69, 1.19; p=0.603) and changes in serum 25-hydroxy vitamin D [25(OH)D] levels (slope: -0.02; 95%CI: -0.15, 0.12; p=0.780). Meta-analysis of data from 6 studies did not find a significant change in plasma leptin concentrations following vitamin D supplementation (MD: -4.51%, 95%CI: -25.13, 16.11, p=0.668; Q=6.41, I(2)=21.97%). Sensitivity analysis showed that this effect size is sensitive to one of the studies; removing it resulted in a significant reduction in plasma leptin levels (MD: -12.81%, 95%CI: -24.33, -1.30, p=0.029). In meta-regression, changes in plasma leptin concentrations following vitamin D supplementation were found to be independent of treatment duration (slope: -1.93; 95%CI: -4.08, 0.23; p=0.080). However, changes in serum 25(OH)D were found to be significantly associated with changes in plasma leptin levels following vitamin D supplementation (slope: 1.05; 95%CI: 0.08, 2.02; p=0.033). In conclusion, current data did not indicate a significant effect of vitamin D supplementation on adiponectin and leptin levels.Revisión por pares
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Mohammed, Sharafudeen Ajimsha. "Myofascial release as a treatment choice for neuromuscular conditions : three randomized controlled trials and a systemic literature review." Thesis, University of Bolton, 2018. http://ubir.bolton.ac.uk/1812/.
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Introduction: Myofascial release (MFR) is a form of manual therapy that involves the application of a low load, long duration stretch to the myofascial complex, intended to restore optimal length, decrease pain, and improve function. MFR is being used to treat patients with a wide variety of conditions, but there is a scarcity of evidence to support its efficacy. Studies are emerging in this field with varying results and conclusions. Analysis of the recent research trials and reviews will be a better way to appraise the quality and reliability of such works. Objective: This work attempts to analyse and summarise the evidence from three randomised controlled trials (RCTs) and one systematic review of the effectiveness of MFR on various neuromuscular conditions and pain. Methodology: Effectiveness of MFR on tension type headache, lateral epicondylitis and chronic low back pain were the RCTs identified for the analysis. The systematic review selected analysed the published RCTs on MFR till 2014. The methodological qualities of the studies were assessed using the PEDro, Centre for Evidence-Based Medicine's (CEBM) Level of Evidence Scale, Risk of Bias (RoB) Analysis Tool and AMSTAR 2. Results: The RCTs analysed in this study were of moderate to high methodological quality (PEDro scale), with higher level of evidence (CEBM scale) and less bias (RoB). The effectiveness of MFR on tension type headache (TTH) was the first among the studies with a moderate methodological quality (6/10 in PEDro), with a 2b level of evidence on the CEBM scale. The study proved that direct technique or indirect technique MFR was more effective than the control intervention for TTH. The second RCT studied MFR for lateral epicondylitis (LE). The study was of a moderately high quality on the PEDro scale (7/10) with a 1b- level in CEBM. The MFR was found more effective than a control intervention for LE in computer professionals. The RCT on chronic low back pain (CLBP) also scored 7/10 in the PEDro scale and 1b in the CEBM scale. This study confirmed that MFR is a useful adjunct to specific back exercises and more helpful than a control intervention for CLBP. All three RCTs stated the usage of self-report measures and underpowered sample size as the major limitations along with a performance bias reported in the TTH trial. The systematic review demonstrated moderate methodological quality as per the AMSTAR 2 tool which analysed 19 RCTs for a result. The literature regarding the effectiveness of MFR was mixed in both quality and results. Omission of a risk of bias analysis was the major limitation of this review. The authors quoted that “MFR may be useful as either a unique therapy or as an adjunct therapy to other established therapies for a variety of conditions”. Conclusion: Critical appraisal is an important element of evidence-based medicine to carefully and systematically examine research to judge its trustworthiness, its value and relevance in a particular context. This review concludes that the three RCTs and the systematic review analysed were completed with moderate to good quality as per various quality measures, but with reported methodological flaws and interpretation biases. These studies with the critical appraisal can act as ‘pavements’ on which high quality future MFR trials and evidence can be built on.
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Uschner, Diane [Verfasser], Ralf-Dieter Akademischer Betreuer] Hilgers, and Klaus [Akademischer Betreuer] [Willmes. "The assessment of bias in randomized controlled clinical trials / Diane Uschner ; Ralf-Dieter Hilgers, Klaus Willmes-von Hinckeldey." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069406/34.
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Uschner, Diane Verfasser], Ralf-Dieter [Akademischer Betreuer] Hilgers, and Klaus [Akademischer Betreuer] [Willmes. "The assessment of bias in randomized controlled clinical trials / Diane Uschner ; Ralf-Dieter Hilgers, Klaus Willmes-von Hinckeldey." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069406/34.
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Chua, Ka Kit. "Randomized controlled clinical trials for the evaluation of efficacy and safety of Chinese medicine in treatment of neurodegenerative diseases." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/231.
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Background: Neurodegenerative diseases (NDD) are very common in the aging population, of which Parkinson’s disease (PD) and Alzheimer disease (AD) are the two most common. Since the etiology of the neuronal death in these diseases remains unclear, currently no curative therapy is available. Traditional Chinese medicine (TCM) has been used to treat certain diseases, which based on their symptoms we now know that they are included PD and AD, for thousands of years. However, our pervious systematic review reports that the quality of current TCM clinical trials related to this area had limited internal validity due to methodological flaws and insufficient data reporting. Methods: This study includes two add-on double-blinded randomized controlled trials (RCT), PD full-scale study and AD pilot study. It aims to provide evidence for the efficacy and safety of two specific TCM decoctions, Jia-Wei-Liu-Jun-Zi Tang (JWLJZT) and Di-tan decoction (DTD) in treating PD and AD, respectively. These clinical trials follow the Consolidated Standards of Reporting Trials (CONSORT) as well as the International Conference on Harmonization guidelines on Good Clinical Practice (GCP). Also, this two RCT obtained the approval from the Human and Animal Research Ethics Committee of Hong Kong Baptist University before the study and registered on the Chinese Clinical Trial Registry. Result: In the PD trial, 111 idiopathic PD patients were randomly assigned to receive either JWLJZT or placebo for 32 weeks. Although there was not significant difference in the primary outcome of Movement Disorder Society Sponsored Revision of Unified PD Rating Scale (MDS-UPDRS) Part I total score (p = 0.216), significant improvements was observed in the secondary outcome of Non-motor symptom assessment scale for Parkinson’s disease (NMSS) total score (p = 0.019), subtype of mood/cognition (p = 0.005) and hallucinations (p = 0.024). In addition, post-hoc analysis showed a significant reduction in constipation (p < 0.001). On the other hand, 40 AD patients were randomly assigned to receive either DTD or placebo for 24 weeks in the AD trial. There was an improvement trend in the primary outcome of the cognitive subscale of Alzheimer’s Disease Assessment Scale (ADAS-cog) total score in the DTD group though the difference relative to the placebo group was not statistically significant (p = 0.315). No significant difference was found in the secondary outcomes. Adverse events were mild and comparable between treatment and placebo groups in both trials. Discussion: JWLJZT did show some improvement in non-motor symptoms, including mood, cognition, and constipation, in PD patients, while, DTD did show a reducing trend in the cognitive impairment based on rigorous RCT. Further study focusing on the effective dosage, pharmacologic mechanism of JWLJZT and DTD are needed to give a fuller picture as well as better support for using them in human being as a routine treatment. In fact, JWLJZT and DTD are the only two examples of TCM for treating NDD. These two clinical trials are served as examples of how to evaluate efficacy and safety of TCM for the treatment of various diseases using rigorous RCT methods and standard. Keywords: Randomized Controlled Trials, Parkinson’s disease, Alzheimer disease, Traditional Chinese medicine, Jia-Wei-Liu-Jun-Zi Tang, Di-tan decoction, Efficacy, Safety
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Abdelghafour, Nassima. "Micropolitics of poverty : how randomized controlled trials address global poverty through the epistemic and political fragmentation of the world." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM042.
Full textAbstract:
La thèse discute l’utilisation des expérimentations contrôlées randomisées en économie du développement. Selon ses promoteurs, cette méthode d’évaluation d’impact, inspirée des essais cliniques, permet d’identifier les interventions les plus efficaces de lutte contre la pauvreté. La thèse interroge cette approche expérimentale de la pauvreté et fait la proposition suivante : les expérimentations randomisées contrôlées produisent une micropolitique de la pauvreté. Elles produisent des fragments du monde, à l’intérieur desquels le problème de la pauvreté globale est confiné, à la fois sur un plan analytique et sur un plan politique. En dramatisant l’importance d’évaluer rigoureusement, les expérimentations contrôlées randomisées ont accentué certaines explications causales (micro, locales, comportementales) de la pauvreté au détriment d’autres (structurelles, globales, historiques), laissées dans l’ombre parce qu’elles ne sont pas solubles dans le dispositif expérimental. L’enquête, ainsi restreinte aux pauvres et à leur environnement immédiat, exclut de l’espace des causes le rôle des pays riches, d’où sont formulées les politiques de lutte contre une pauvreté pourtant dite « globale ». Empiriquement, la thèse s’appuie sur l’ethnographie d’une expérimentation contrôlée randomisée, en Afrique de l’EstThe dissertation discusses the use of randomized controlled trials (RCTs) in poverty action. RCT proponents claim that this impact evaluation method, inspired from clinical trials, enables to identify the most efficient poverty-reduction interventions. The dissertation questions this experimental approach to poverty (recently rewarded by the Nobel memorial prize in economics). The thesis main contention is that RCTs produce a micropolitics of poverty. They proceed through the epistemic and political fragmentation of the world. They define a patchy, discontinuous space in which global poverty can be analyzed according to a standardized protocol, and within which poverty action can be contained. Empirically, the dissertation is based on the ethnographic account of an RCT, in East Africa