Questions tagged [clinical-trials]

Clinical trials are studies designed to test the safety and efficacy of new clinical interventions such as drugs or medical devices.

Clinical trials are studies designed to test the safety and efficacy of new clinical interventions such as drugs or medical devices. Clinical trials differ from other aspects of medical research for three main reasons:

  • Statistical methodology: Clinical trials have strict design requirements to avoid the introduction of bias in evaluating a new intervention. Clinical trial design is a specialized subset of biostatistics and involves knowledge of design of experiments, power and sample size calculations, and various modeling techniques to control for confounding factors.

  • Regulation: Clinical trials are used by many regulatory agencies to determine whether or not a drug is safe for use in patient care. Because of the importance of clinical trials in licensing and regulating new drugs and medical devices, clinical trials are subject to strict regulatory requirements regarding recordkeeping and data storage.

  • Goals of research: Clinical trials are primarily concerned with safety and efficacy. Initial trials may simply investigate whether or not the drug is safe for use in humans, by using relatively healthy subjects. Subsequent trials look for efficacy - that the new drug gives results that are at least as good as the current gold standard during a clinical trial. Drug effectiveness - the ability of the drug to successfully treat illness in actual clinical practice - is not usually assessed in a clinical trial, which is focused strictly on the experimental design that compares the new intervention to an existing intervention.

Clinical trials questions should be tagged using this tag; the epidemiology tag should be used for other health-related research that are not clinical trials.

439 questions
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How should one control for group and individual differences in pre-treatment scores in a randomised controlled trial?

Andrew Gelman, in the book he wrote with Jennifer Hill, states in Chapter 9, (section 9.3), on page 177: It is only appropriate to control for pre-treatment predictors, or, more generally, predictors that would not be affected by the treatment…
user6666
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Does Intention-to-treat apply to the cases that should have been excluded but not able to do so during recruitment?

I am working on a pharmacist-supported new medicine randomised trial. One of the criteria during the recruitment was that if a patient used medicine previously, he/she should not be recruited. However, there were some patients that simply forgot…
Fred
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In relation to clinical trials, what is clinical reasoning in contrast to statistical reasoning?

I read Clinical Trials, a Methodologic Perspective (S. Piantadosi) as I was suggested by one of you. According to the author: A trialist must understand two different modes of thinking that support the science-clinical and statistical. They…
ocram
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Can we say a control / placebo group exists in a complex intervention?

In the case of something like acupuncture (as an example), it is very hard to set a placebo group or control group, since this therapy is not like taking drugs. Lets say if the needle is not in the right place (as a sort of placebo treatment), it…
Enzo Kwok
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Clinical trials significance

I have been a studying high energy physics (HEP) for the last few years but I recently started working on a project in medical imaging. I have been a little surprised (not entirely I was aware that 95% was commonly used) to find major studies…
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Does Intention-to-Treat reduce bias in a non-randomised trial?

I am involved in a trial comparing the withdrawal patients staying in an in-patient unit experience after discontinuing either of two drugs. The drug they were taking before they commenced abstinence will not be not randomised. A reviewer on the…
llewmills
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For a clinical study, What statistical analysis methods should I add or change

I am performing a statistical analysis of a clinical study where the dependent variable is a binary variable (whether or not a myocardial infarction occurred). As a novice, I first learned the following statistical analyses, but I would like to add…
zhiheng yi
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Score Questionare for different age groups combined

Lets say we have two questionares for two different age groups. One has 100 items the other 150 items, where we can answer each question with 0 - 2. Then we calculate the mean value of all answers given. So for the first questionare this is a value…
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Proof of robustness of CRD vs RBD vs RCBD

I read quite a lot of papers about how RCT (random control trials) performs better than a simple naive experiment design. It's intuitive... however... i don't trust intuition and i'm looking for a textbook or paper that provide the following…
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What factors decide on number and frequency of interim analyses in a sequental clinical trial?

I wonder if I can be advised on design for a sequential clinical trial with interim analyses designed to stop the trial early for efficacy or futility ? What factors decide on number and frequency of interim analyses? I can see the first interim…
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Analysis of randomised controlled trial with continuous follow up

The scenario is as follows: We are recruiting participants to a randomised controlled trial of a novel intervention. The recruitment will extend over a period of six months. Participants are randomised individually (no strata, blocks, etc.).…
Fgold
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Analysis of prospective case-control clinical data

I have a question on the best way to analyse a particular set of clinical data. The background to the study is assessing the effect of treatment delay on the time to resolution of a particular disease. If we delay treatment, does this lead to an…
user117006
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