NBME 22 Open-label clinical trial (NBME Answers)

Retired NBME 22 Answers

nbme22/Block 4/Question#20 (reveal difficulty score)
During a study of symptomatic proximal deep ...
Open-label clinical trial 🔍 / 📺 / 🌳 / 📖
tags: biostats

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submitted by ∗asharm10(37)

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When you are comparing the therapeutic effects of two drugs it's a clinical trial and when both the patients and providers know which drug it's open label. Clinical trial could be done between tx/control or tx/tx. It can't be crossover as there is no wash out phase

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weirdmed51 What’s wash out phase? +

l0ud_minority @weirdmed51 washout phase is when you are trying to get a drug out of your system example being when treating depression and transitioning from an MAOI to an SSRI you have to wait a couple of weeks for MAO regeneration as to avoid serotonin syndrome. +

ankigravity To connect to the question, a crossover study is one in which participants serve as there own controls. That is, they get drug A, then they have a washout period where the drug is allowed to clear from their system, then they receive drug B. The researchers can then have the participants serve as there own control. +

ankigravity Just to add, drug A or B can also be a placebo as well. +

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submitted by ∗aesalmon(95)

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Clinical trial - compares therapeutic benefits of 2+ treatments (warfarin vs. dalteparin) Open-label - both the health providers and the pt are aware of the drug being given

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jackie_chan How are we supposed to know in the question the patients and providers are aware that they know what they are being given? +1

haydenelise I went back and forth about it, but in the end figured that they were aware since one regimen involved subQ injection + oral med and the other was subQ injection alone with no oral placebo. +3

weirdmed51 @haydenelise that was really clever! +

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submitted by ∗hello(429)

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Why isn't this a cohort study?

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drdoom This is a cohort study! (Since it involves splitting people into "groups"; group = cohort.) But the stem asks what "best describes" the design. So, yes, it's a cohort study but a more precise ("more specific") description is Open-label. In other words, "Open-label clinical trial" is a type of cohort study, and, in this case, "Open-label" is a more precise description of what is described in the stem. +7

drdoom For a more technical explanation of "Cohort studies", see the definition from the National Library of Medicine: https://meshb.nlm.nih.gov/record/ui?ui=D015331 +1

angelaq11 It is a cohort, just as @drdoom said, but it isn't an "Observational" one. +3

pg32 It's actually not a cohort study, imo. In a cohort you find people with an exposure and see if they develop some outcome. In this experiment, people were RANDOMLY ASSIGNED to the different exposures. That doesn't happen in cohorts. +10

pg32 It may be a cohort in that these people are in groups, but for the purposes of Step 1, I don't think we will deal with typical "Cohort" studies in which participants are randomly assigned. +2

ashli777 you don't administer an intervention in a cohort study, you just observe what happens. it is an observational study. +

drdoom ^ i retract my earlier subcomment! thanks @ashli777 and @pg32 — you guys are right that cohorts do not intervene! in two senses: (1) there is no treatment intervention and (2) there is no “assignment” intervention (either randomly or by selection; that is, investigators do not DESIGN or DETERMINE how groups are formed, even if that means random determination by computer). +2

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submitted by ∗niboonsh(409)

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I am confusion. why wouldnt this be a cross over study?

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shokay there is no washout period and the order of drugs given isn't switched +7

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