Scientific and Ethical Issues in Equivalence Trials
... are performed to assess the probability that a given difference is obtained by chance. In equivalence trials, this difference ideally would be zero, although a proof of exact equality is not possible.16 In practice, this issue is resolved by defining an arbitrary practical equivalence margin, also c ...
... are performed to assess the probability that a given difference is obtained by chance. In equivalence trials, this difference ideally would be zero, although a proof of exact equality is not possible.16 In practice, this issue is resolved by defining an arbitrary practical equivalence margin, also c ...
Treating Individuals-External validity of randomised controlled trials
... “Between measurements based on RCTs and benefit . . . in the community there is a gulf which has been much under-estimated” A L Cochrane, 19711 “At its best a trial shows what can be accomplished with a medicine under careful observation and certain restricted conditions. The same results will not in ...
... “Between measurements based on RCTs and benefit . . . in the community there is a gulf which has been much under-estimated” A L Cochrane, 19711 “At its best a trial shows what can be accomplished with a medicine under careful observation and certain restricted conditions. The same results will not in ...
Bias in a Randomized Controlled Trial and how these can be
... part of a research investigator regarding the comparative intervention merits of each arm in a clinical trial. As this may lead to an insuperable obstacle to an ethical commencement of a clinical trial, now there is a general understanding, that this concept of clinical equipoise is satisfied if the ...
... part of a research investigator regarding the comparative intervention merits of each arm in a clinical trial. As this may lead to an insuperable obstacle to an ethical commencement of a clinical trial, now there is a general understanding, that this concept of clinical equipoise is satisfied if the ...
- Clinical Gastroenterology and Hepatology
... Therefore, a large-scale, multicenter, methodologically rigorous RCT was conducted to definitively evaluate the efficacy of prophylactic rectal indomethacin for preventing PEP in high-risk cases.5 In this study, rectal indomethacin was associated with 7.7% absolute risk reduction (number needed to tre ...
... Therefore, a large-scale, multicenter, methodologically rigorous RCT was conducted to definitively evaluate the efficacy of prophylactic rectal indomethacin for preventing PEP in high-risk cases.5 In this study, rectal indomethacin was associated with 7.7% absolute risk reduction (number needed to tre ...
Centre for Philosophy of Natural and Social Science
... administration or non-administration of the therapy being tested) tends to be given a less central role. There is nothing approaching complete consistency in the statistical literature but Grage and Zelen again express a view that would, I think, meet widespread agreement amongst orthodox statistici ...
... administration or non-administration of the therapy being tested) tends to be given a less central role. There is nothing approaching complete consistency in the statistical literature but Grage and Zelen again express a view that would, I think, meet widespread agreement amongst orthodox statistici ...
Some caveats for outcome adaptive randomization in clinical trials
... The Fair Contin method exhibits as much or slightly more bias than the AR designs, while the Fair GS design reduces the bias by 66% to 71% compared to all the other designs. Figure 2 gives the distributions of the posterior mean of ∆ for the Fair GS, AR(n/2N), and AR(1) designs for the three cases w ...
... The Fair Contin method exhibits as much or slightly more bias than the AR designs, while the Fair GS design reduces the bias by 66% to 71% compared to all the other designs. Figure 2 gives the distributions of the posterior mean of ∆ for the Fair GS, AR(n/2N), and AR(1) designs for the three cases w ...
CLINICAL TRIAL DESIGN
... – Placebo was used, but was distinguishable – Many on placebo dropped out of study – Those who knew they were on vitamin C reported fewer cold symptoms and duration than those on vitamin who didn't know ...
... – Placebo was used, but was distinguishable – Many on placebo dropped out of study – Those who knew they were on vitamin C reported fewer cold symptoms and duration than those on vitamin who didn't know ...
Evidence-Based Drug Therapy Evaluation
... • It does not determine place in therapy. • Value not assessed. • Often there are many unanswered questions at the time a drug is approved. – Limited numbers and types of patients – Limited duration of studies – May not know outcomes of greatest interest ...
... • It does not determine place in therapy. • Value not assessed. • Often there are many unanswered questions at the time a drug is approved. – Limited numbers and types of patients – Limited duration of studies – May not know outcomes of greatest interest ...
ppt slides
... inform health-care decisions by providing evidence on the effectiveness, benefits, and harms of different treatment options. • Evidence is generated from research studies that compare drugs, medical devices, tests, surgeries, or ways to deliver health care. ...
... inform health-care decisions by providing evidence on the effectiveness, benefits, and harms of different treatment options. • Evidence is generated from research studies that compare drugs, medical devices, tests, surgeries, or ways to deliver health care. ...
Clinical Protocol Irritable Bowel Syndrome (IBS) Clinical Protocol
... Consider a soluble fibre (psyllium) as first line therapy in patients with IBS-C, possibly adding an osmotic laxative, with a trial of selective serotonin reuptake inhibitors as second line therapy In patients with bloating or IBS-D as the predominant symptom consider the use of a probiotic (such as ...
... Consider a soluble fibre (psyllium) as first line therapy in patients with IBS-C, possibly adding an osmotic laxative, with a trial of selective serotonin reuptake inhibitors as second line therapy In patients with bloating or IBS-D as the predominant symptom consider the use of a probiotic (such as ...
The role of randomization in clinical trials
... In recent years a number of proposals have been made for the use of dynamic systems of allocation, in which the assignment to be made for any one patient depends in some way on the previous course of events. A distinction should be made between (i) schemes aiming to provide a better balance of progn ...
... In recent years a number of proposals have been made for the use of dynamic systems of allocation, in which the assignment to be made for any one patient depends in some way on the previous course of events. A distinction should be made between (i) schemes aiming to provide a better balance of progn ...
comparative efficacy and acceptability of pharmacological
... will generate descriptive statistics for trial and study population characteristics across all eligible trials. We will assess the presence of clinical heterogeneity within each pairwise comparison by comparing these characteristics.13 Assessment of transitivity across treatment comparisons The assu ...
... will generate descriptive statistics for trial and study population characteristics across all eligible trials. We will assess the presence of clinical heterogeneity within each pairwise comparison by comparing these characteristics.13 Assessment of transitivity across treatment comparisons The assu ...
DE TESTIMONIO On the evidence for decisions about
... ingredient of most aspects of the decision-making process.5 Randomised controlled trials The introduction of RCTs in the middle of the 20th century has had a profound impact on the practice of medicine and its essential features are well described.4,6,7 It © Royal College of Physicians, 2008. All ri ...
... ingredient of most aspects of the decision-making process.5 Randomised controlled trials The introduction of RCTs in the middle of the 20th century has had a profound impact on the practice of medicine and its essential features are well described.4,6,7 It © Royal College of Physicians, 2008. All ri ...
What is a Clinical Trial
... intent is to balance the number of individuals in each group without specifying that an individual must be assigned to a specific group The chances that an individual will be assigned to a treatment or control group are allowed to vary based on prior ...
... intent is to balance the number of individuals in each group without specifying that an individual must be assigned to a specific group The chances that an individual will be assigned to a treatment or control group are allowed to vary based on prior ...
horn_b
... 1. All interventions considered to determine relative contribution of each. 2. Hypotheses can be focused or broad 3. Minimal selection criteria to maximize generalizability and external validity 4. Detailed characterization of the individual through the use of robust measures of patient acuity & ...
... 1. All interventions considered to determine relative contribution of each. 2. Hypotheses can be focused or broad 3. Minimal selection criteria to maximize generalizability and external validity 4. Detailed characterization of the individual through the use of robust measures of patient acuity & ...
Practice Guidelines from Randomized Clinical Trials
... • In late ‘50’s and early ‘60’s it was recommended to pregnant women by their OB/GYN’s to control morning sickness. • Later found to cause serious birth defects and miscarriages. • Led to serious birth defects of more than 10,000 children. ...
... • In late ‘50’s and early ‘60’s it was recommended to pregnant women by their OB/GYN’s to control morning sickness. • Later found to cause serious birth defects and miscarriages. • Led to serious birth defects of more than 10,000 children. ...
Randomized Controlled Trials (Experimental Studies)
... studies in which a direct comparison is made between two or more treatment groups, one of which serves as a control for the other. Study subjects are randomly allocated into the differing treatment groups, and all groups are followed over time to observe the effect of the different treatments. The c ...
... studies in which a direct comparison is made between two or more treatment groups, one of which serves as a control for the other. Study subjects are randomly allocated into the differing treatment groups, and all groups are followed over time to observe the effect of the different treatments. The c ...
Randomized clinical trials
... textbooks, and others. One accepts their analysis of the medical information on faith and this dictates what one actually does for his or her patient. Deduction is the prospective analysis and application of the results of critical appraisal of formal randomized clinical trials. This method of deci ...
... textbooks, and others. One accepts their analysis of the medical information on faith and this dictates what one actually does for his or her patient. Deduction is the prospective analysis and application of the results of critical appraisal of formal randomized clinical trials. This method of deci ...
Are Observational Studies More Informative Than Randomized
... concern in the scientific and lay communities.17 In a population-based case-control study of hypertensive patients carried out among enrollees of the Group Health Cooperative of Puget Sound, Psaty et al15 reported a 60% increase in the risk of myocardial infarction for calcium-channel blockers compa ...
... concern in the scientific and lay communities.17 In a population-based case-control study of hypertensive patients carried out among enrollees of the Group Health Cooperative of Puget Sound, Psaty et al15 reported a 60% increase in the risk of myocardial infarction for calcium-channel blockers compa ...
Selection bias will always be present in case series
... Secondary Considerations Lending Support for Concluding Efficacy: Factoring in the following conditions may decrease uncertainty: a. Immediacy of effect which may increase confidence in the effectiveness of the intervention or technology not only because of temporal proximity, but also because a del ...
... Secondary Considerations Lending Support for Concluding Efficacy: Factoring in the following conditions may decrease uncertainty: a. Immediacy of effect which may increase confidence in the effectiveness of the intervention or technology not only because of temporal proximity, but also because a del ...
International prospective register of systematic reviews
... will consider the number of individuals with SSAE(s), rather than the number of SSAEs. We will present the cumulative estimates as follows. We will use a random effects Mantel-Haenszel method, which is more robust when pooling sparse data. For each meta-analysis, we will report the chi-squared p-val ...
... will consider the number of individuals with SSAE(s), rather than the number of SSAEs. We will present the cumulative estimates as follows. We will use a random effects Mantel-Haenszel method, which is more robust when pooling sparse data. For each meta-analysis, we will report the chi-squared p-val ...
Design and Analysis of Clinical Trials
... Reduces variance, often resulting in smaller required sample sizes Disadvantages Only useful in certain disease settings May introduce "order" effects Nature of intervention may be influenced by results of first study period ...
... Reduces variance, often resulting in smaller required sample sizes Disadvantages Only useful in certain disease settings May introduce "order" effects Nature of intervention may be influenced by results of first study period ...
Rajini Ramana - The Cambridge MRCPsych Course
... levels of ≥0.5 meq/liter and had a minimum treatment duration of 2 weeks. Bauer M, Döpfmer S: Lithium augmentation in treatmentresistantdepression: meta-analysis of placebo-controlled studies. J Clin ...
... levels of ≥0.5 meq/liter and had a minimum treatment duration of 2 weeks. Bauer M, Döpfmer S: Lithium augmentation in treatmentresistantdepression: meta-analysis of placebo-controlled studies. J Clin ...
Randomized controlled trial
A randomized controlled trial (or randomized control trial; RCT) is a type of scientific (often medical) experiment, where the people being studied are randomly allocated one or other of the different treatments under study. The RCT is often considered the gold standard for a clinical trial. RCTs are often used to test the efficacy or effectiveness of various types of medical intervention and may provide information about adverse effects, such as drug reactions. Random assignment of intervention is done after subjects have been assessed for eligibility and recruited, but before the intervention to be studied begins.Random allocation in real trials is complex, but conceptually, the process is like tossing a coin. After randomization, the two (or more) groups of subjects are followed in exactly the same way, and the only differences between the care they receive, for example, in terms of procedures, tests, outpatient visits, and follow-up calls, should be those intrinsic to the treatments being compared. The most important advantage of proper randomization is that it minimizes allocation bias, balancing both known and unknown prognostic factors, in the assignment of treatments.The terms ""RCT"" and randomized trial are sometimes used synonymously, but the methodologically sound practice is to reserve the ""RCT"" name only for trials that contain control groups, in which groups receiving the experimental treatment are compared with control groups receiving no treatment (a placebo-controlled study) or a previously tested treatment (a positive-control study). The term ""randomized trials"" omits mention of controls and can describe studies that compare multiple treatment groups with each other (in the absence of a control group). Similarly, although the ""RCT"" name is sometimes expanded as ""randomized clinical trial"" or ""randomized comparative trial"", the methodologically sound practice, to avoid ambiguity in the scientific literature, is to retain ""control"" in the definition of ""RCT"" and thus reserve that name only for trials that contain controls. Not all randomized clinical trials are randomized controlled trials (and some of them could never be, in cases where controls would be impractical or unethical to institute). The term randomized controlled clinical trials is a methodologically sound alternate expansion for ""RCT"" in RCTs that concern clinical research; however, RCTs are also employed in other research areas, including many of the social sciences.