Randomization

2018 ◽  
pp. 87-104
Author(s):  
Juliana C Ferreira ◽  
Ben M. W. Illigens ◽  
Felipe Fregni
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Randomized Clinical Trial ◽  
Selection Bias ◽  
Allocation Concealment ◽  
Small Sample ◽  
Adaptive Randomization ◽  
Entire Process ◽  
Advantages And Disadvantages ◽  
Small Sample Sizes

Chapter 5 gives the reader an overview of a major important feature in every randomized clinical trial: the process of randomization. This chapter describes the main features of randomization, its importance, advantages, and disadvantages. It also discusses the most common methods of randomization (simple randomization, blocked randomization, stratified randomization, adaptive randomization), as well as what the investigator should take into consideration when choosing among these options. In this scenario, the challenges of defining a method in clinical trials with small sample sizes are also discussed. Additionally, the chapter explores the consequences that may arise from lack of randomization, such as selection bias. It also focuses on defining allocation concealment and its importance to the appropriate conduction of a study. In this chapter, the reader is taken through the entire process—from choosing a suitable randomization option to ensuring the appropriate implementation of the selected method.

scholarly journals Unification of treatments and interventions for tinnitus patients (UNITI): a study protocol for a multi-center randomized clinical trial

2021 ◽  
Author(s):  
Stefan Schoisswohl ◽  
Berthold Langguth ◽  
Martin Schecklmann ◽  
Benjamin Boecking ◽  
Christopher Cederroth ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Randomized Clinical Trial ◽  
Hearing Aids ◽  
Behavioral Therapy ◽  
Primary Outcome Measure ◽  
Small Sample ◽  
Personalized Treatment ◽  
Treatment Approaches ◽  
Multiple Systems ◽  
Small Sample Sizes

Abstract Background Tinnitus represents a relatively common condition in the global population accompanied by various comorbidities and severe burden in many cases. Nevertheless, there is currently no general treatment or cure, presumable due to the heterogeneity of tinnitus with its wide variety of etiologies and tinnitus phenotypes. Hence, most treatment studies merely demonstrated improvement in a subgroup of tinnitus patients. The majority of studies are characterized by small sample sizes, unstandardized treatments and assessments or applications of intervention targeting only a single organ level. Combinatory treatment approaches, potentially targeting multiple systems as well as treatment personalization might provide remedy and enhance treatment responses. The aim of the present study is to systematically examine established tinnitus therapies both alone and in combination in a large sample of tinnitus patients. Further it wants to provide the basis for personalized treatment approaches by evaluating a specific decision support system developed as part of an EU-funded collaborative project (Unification of treatments and interventions for tinnitus patients; UNITI-project). Methods/ Study design: This is a multi-center parallel-arm randomized clinical trial conducted at five different clinical sites over the EU. The effect of four different tinnitus therapy approaches (sound therapy, structured counselling, hearing aids, cognitive behavioral therapy) applied over a time period of 12 weeks as a single or rather a combinatory treatment in a total number of 500 chronic tinnitus patients will be investigated. Assessments and interventions are harmonized over the involved clinical sites. The primary outcome measure focuses on the domain tinnitus distress assessed via the Tinnitus Handicap Inventory. Discussion Results and conclusions from the current study might not only provide an essential contribution to combinatory and personalized treatment approaches in tinnitus but could also provide more profound insights in the heterogeneity of tinnitus, representing an important step towards a cure for tinnitus. Trial registration: ClinicalTrials.gov: NCT04663828. Registered on 11. December 2020

scholarly journals Unification of Treatments and Interventions for Tinnitus Patients (UNITI): a study protocol for a multi-center randomized clinical trial

Trials ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Stefan Schoisswohl ◽  
Berthold Langguth ◽  
Martin Schecklmann ◽  
Alberto Bernal-Robledano ◽  
Benjamin Boecking ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Randomized Clinical Trial ◽  
Hearing Aids ◽  
Behavioral Therapy ◽  
Primary Outcome Measure ◽  
Small Sample ◽  
Personalized Treatment ◽  
Treatment Approaches ◽  
Multiple Systems ◽  
Small Sample Sizes

Abstract Background Tinnitus represents a relatively common condition in the global population accompanied by various comorbidities and severe burden in many cases. Nevertheless, there is currently no general treatment or cure, presumable due to the heterogeneity of tinnitus with its wide variety of etiologies and tinnitus phenotypes. Hence, most treatment studies merely demonstrated improvement in a subgroup of tinnitus patients. The majority of studies are characterized by small sample sizes, unstandardized treatments and assessments, or applications of interventions targeting only a single organ level. Combinatory treatment approaches, potentially targeting multiple systems as well as treatment personalization, might provide remedy and enhance treatment responses. The aim of the present study is to systematically examine established tinnitus therapies both alone and in combination in a large sample of tinnitus patients. Further, it wants to provide the basis for personalized treatment approaches by evaluating a specific decision support system developed as part of an EU-funded collaborative project (Unification of treatments and interventions for tinnitus patients; UNITI project). Methods/study design This is a multi-center parallel-arm randomized clinical trial conducted at five different clinical sites over the EU. The effect of four different tinnitus therapy approaches (sound therapy, structured counseling, hearing aids, cognitive behavioral therapy) applied over a time period of 12 weeks as a single or rather a combinatory treatment in a total number of 500 chronic tinnitus patients will be investigated. Assessments and interventions are harmonized over the involved clinical sites. The primary outcome measure focuses on the domain tinnitus distress assessed via the Tinnitus Handicap Inventory. Discussion Results and conclusions from the current study might not only provide an essential contribution to combinatory and personalized treatment approaches in tinnitus but could also provide more profound insights in the heterogeneity of tinnitus, representing an important step towards a cure for tinnitus. Trial registration ClinicalTrials.gov NCT04663828. Registered on 11 December 2020.

Is the future for clinical trials internet-based? A cluster randomized clinical trial

2005 ◽  
Vol 2 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Jennifer Litchfield ◽  
Jenny Freeman ◽  
Henrik Schou ◽  
Mark Elsley ◽  
Robert Fuller ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Randomized Clinical Trial ◽  
The Future ◽  
Cluster Randomized

Melatonin reduces the mortality of severely-infected COVID-19 patients

2021 ◽  
Vol 4 (4) ◽  
pp. 613-616
Author(s):  
Dun-Xian Tan ◽  
Russel J Reiter
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Mortality Rate ◽  
Randomized Clinical Trial ◽  
Control Group ◽  
Mortality Reduction ◽  
Single Center ◽  
Open Label ◽  
Melatonin Treatment ◽  
The World

SARS-CoV-2 has ravaged the population of the world for two years. Scientists have not yet identified an effective therapy to reduce the mortality of severe COVID-19 patients. In a single-center, open-label, randomized clinical trial, it was observed that melatonin treatment lowered the mortality rate by 93% in severely-infected COVID-19 patients compared with the control group (see below). This is seemingly the first report to show such a huge mortality reduction in severe COVID-19 infected individuals with a simple treatment. If this observation is confirmed by more rigorous clinical trials, melatonin could become an important weapon to combat this pandemic.

scholarly journals Shear Bond Strength of Brackets Bonded with Self-Etching Primers Compared to Conventional Acid-Etch Technique: A Randomized Clinical Trial

2019 ◽  
Author(s):  
Nasrin Farhadian ◽  
Amirfarhang Miresmaeili ◽  
Vahid Shahidi Zandi
Keyword(s):  
Clinical Trial ◽  
Bond Strength ◽  
Randomized Clinical Trial ◽  
Shear Bond Strength ◽  
Allocation Concealment ◽  
Wilcoxon Test ◽  
Adhesive Remnant Index ◽  
Significant Difference ◽  
Acid Etch ◽  
Registration Number

Objectives: The purpose of this randomized clinical trial (RCT) was to compare the shear bond strength (SBS) of orthodontic brackets bonded to enamel with conventional acid-etch (AE) technique and self-etching primers (SEP). Materials and Methods: Twenty-two patients, requiring extraction of two bicuspids for orthodontic reasons, were recruited. In each individual, following blinding and allocation concealment, one intact premolar received conventional AE, whereas the contralateral premolar received SEP with a split-mouth design. Bonded brackets remained in the oral cavity for two months. Afterward, the teeth were extracted without debonding the brackets. SBS and adhesive remnant index (ARI) were measured using a Universal Instron machine and a stereomicroscope, respectively. Results: The mean SBS of the conventional AE and SEP groups was 9.53 and 9.20 MPa, respectively. Paired t-test showed no statistically significant difference between the two groups (P=0.096). Comparison of ARI between the two groups, using Wilcoxon test, indicated that significantly less adhesive remained on enamel with brackets bonded with SEP compared to brackets bonded with conventional AE (P<0.001) although the SBS was higher in the AE group. Conclusion: The present study indicated that although there is no significant difference in SBS between SEP and conventional AE for bonding orthodontic metal brackets, the amount of residual adhesive on the enamel surface is significantly less with SEP than with conventional AE. (IRCT registration number: IRCT201705099086N3).

scholarly journals Guidelines on how to assess the validity of results presented in subgroup analysis of clinical trials

2002 ◽  
Vol 57 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Edson Duarte Moreira ◽  
Ezra Susser
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Randomized Clinical Trial ◽  
Subgroup Analysis ◽  
Observational Studies ◽  
Randomized Clinical Trials ◽  
Usual Method ◽  
Validity Of Results ◽  
Results Of Treatment ◽  
Trial Participants

In observational studies, identification of associations within particular subgroups is the usual method of investigation. As an exploratory method, it is the bread and butter of epidemiological research. Nearly everything that has been learned in epidemiology has been derived from the analysis of subgroups. In a randomized clinical trial, the entire purpose is the comparison of the test subjects and the controls, and when there is particular interest in the results of treatment in a certain section of trial participants, a subgroup analysis is performed. These subgroups are examined to see if they are liable to a greater benefit or risk from treatment. Thus, analyzing patient subsets is a natural part of the process of improving therapeutic knowledge through clinical trials. Nevertheless, the reliability of subgroup analysis can often be poor because of problems of multiplicity and limitations in the numbers of patients studied. The naive interpretation of the results of such examinations is a cause of great confusion in the therapeutic literature. We emphasize the need for readers to be aware that inferences based on comparisons between subgroups in randomized clinical trials should be approached more cautiously than those based on the main comparison. That is, subgroup analysis results derived from a sound clinical trial are not necessarily valid; one must not jump to conclusions and accept the validity of subgroup analysis results without an appropriate judgment.

Extracorporeal Membrane Oxygenation and the Play the Winner Rule

PEDIATRICS ◽  
1985 ◽  
Vol 76 (4) ◽  
pp. 622-623
Author(s):  
NIGEL PANETH ◽  
SYLVAN WALLENSTEIN
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Extracorporeal Membrane Oxygenation ◽  
Randomized Clinical Trial ◽  
Conventional Treatment ◽  
Randomized Clinical Trials ◽  
Ethical Problem ◽  
Therapeutic Trial ◽  
Membrane Oxygenation ◽  
Treatment Comparisons

The therapeutic trial comparing extracorporeal membrane oxygenation with conventional treatment in neonatal respiratory failure reported by Bartlett et al (Pediatrics 1985;76:479-487) uses a method of comparing treatments unlikely to be familiar to most pediatricians. Known as the "randomized play the winner" method, it has thus far been little used in clinical research. Most clinical investigators consider the conventional randomized clinical trial to be the last word in treatment comparisons. But randomized clinical trials are costly, cumbersome, and to some observers less than ideal ethically. The ethical problem arises from the fact that during a "successful" randomized clinical trial (ie, one that demonstrates a significant advantage to one treatment) about half of the trial subjects will receive a treatment which, at the end of the trial, will be known to be inferior.

Simulation Modeling as a Decision-Making Aid in Economic Evaluation for Randomized Clinical Trials

2011 ◽  
pp. 1738-1758
Author(s):  
Tillal Eldabi ◽  
Robert D. Macredie ◽  
Ray J. Paul
Keyword(s):  
Clinical Trial ◽  
Decision Making ◽  
Clinical Trials ◽  
Economic Evaluation ◽  
Simulation Model ◽  
Randomized Clinical Trial ◽  
Simulation Modeling ◽  
Randomized Clinical Trials ◽  
Healthcare Systems ◽  
Modeling Process

This chapter reports on the use of simulation in supporting decision-making about what data to collect in a randomized clinical trial (RCT). We show how simulation also allows the identification of critical variables in the RCT by measuring their effects on the simulation model’s “behavior.” Healthcare systems pose many of the challenges, including difficulty in understanding the system being studied, uncertainty over which data to collect, and problems of communication between problem owners. In this chapter we show how simulation also allows the identification of critical variables in the RCT by measuring their effects on the simulation model’s “behavior.” The experience of developing the simulation model leads us to suggest simple but extremely valuable lessons. The first relates to the inclusion of stakeholders in the modeling process and the accessibility of the resulting models. The ownership and confidence felt by stakeholders in our case is, we feel, extremely important and may provide an example to others developing models.

scholarly journals True and false positive rates for different criteria of evaluating statistical evidence from clinical trials

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Don van Ravenzwaaij ◽  
John P. A. Ioannidis
Keyword(s):  
Clinical Trials ◽  
Confidence Intervals ◽  
False Positive ◽  
Evaluation Criteria ◽  
Small Sample ◽  
Statistical Evidence ◽  
Bayes Factors ◽  
True Positive ◽  
Small Sample Sizes ◽  
Meta Analyses

Abstract Background Until recently a typical rule that has often been used for the endorsement of new medications by the Food and Drug Administration has been the existence of at least two statistically significant clinical trials favoring the new medication. This rule has consequences for the true positive (endorsement of an effective treatment) and false positive rates (endorsement of an ineffective treatment). Methods In this paper, we compare true positive and false positive rates for different evaluation criteria through simulations that rely on (1) conventional p-values; (2) confidence intervals based on meta-analyses assuming fixed or random effects; and (3) Bayes factors. We varied threshold levels for statistical evidence, thresholds for what constitutes a clinically meaningful treatment effect, and number of trials conducted. Results Our results show that Bayes factors, meta-analytic confidence intervals, and p-values often have similar performance. Bayes factors may perform better when the number of trials conducted is high and when trials have small sample sizes and clinically meaningful effects are not small, particularly in fields where the number of non-zero effects is relatively large. Conclusions Thinking about realistic effect sizes in conjunction with desirable levels of statistical evidence, as well as quantifying statistical evidence with Bayes factors may help improve decision-making in some circumstances.

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