Prática de Shadowing: Sequential, Multiple Assignment, Randomized Trial Designs With Dr Kidwell - Aprenda a falar inglês com vídeo
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Hello, and welcome to JAMA Evidence, our podcast series based on core issues in evidence -based medicine.
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Today, we will be discussing sequential, multiple assignment, randomized trial designs.
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I'm your host, Dr. Roger Lewis, statistical editor for JAMA and co -editor of the JAMA Guide to Statistics and Methods series.
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I'm here with Dr. Kelly Kidwell.
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Dr. Kidwell, thank you so much for joining us.
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Can you go ahead and tell our listeners a little bit about yourself?
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Sure.
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Thank you so much for having me, Roger.
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I'm Kelly Kidwell.
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I'm a professor of biostatistics at the University of Michigan School of Public Health, and my expertise is in clinical trial design and analysis,
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and in particular, the sequential multiple assignment randomized trials or SMART design.
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Well, again, thank you so much for joining us.
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So the name of this approach to a trial design is a bit daunting, so let's try to break it up a little bit.
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So for each of those terms, can you go ahead and tell us what it means and then how we put it together in designing a clinical trial?
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I completely agree with you that the vocabulary around smart design is quite daunting.
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So what an excellent first question to start with.
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So sequential is about a few things.
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One is that we're interested in sequences of treatments.
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And in this clinical trial design, we're going to have sequential randomization.
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So those terms aren't next to each other, but that's really what's happening and defines this trial,
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such that at least some group of participants will be randomized twice in sequence.
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So usually there's some upfront randomization
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and then a subsequent randomization for some group of participants based on their response to the initial treatment.
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And so that multiple assignment comes into the fact that we'll have this sequential treatment assignment.
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So individuals could be assigned to multiple treatments.
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And this is all wrapped up in a clinical trial.
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So we're going to use this SMART clinical trial tool to give us robust evidence for sequences of treatments
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that adapt to individual responses or patient status.
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So in contrast, in a traditional or a simpler clinical trial design.
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We just randomize once, and then the patient either does well
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or perhaps doesn't do so well on the treatment to which they are assigned.
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And if they don't do well, we often have some sort of rescue therapy or they have to leave the trial.
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So how is the experience of a patient or a participant different in a SMART design?
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Right.
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So in a general, standard, traditional randomized clinical trial, we're really looking at one point in time,
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sort of this trial in a vacuum.
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The SMART is going to say, let's look at that patient over the course of care.
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So in a standard trial where you might stop collecting their data and treating them off trial if they didn't respond, we actually want to use that data.
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And in fact, we might want to randomize the treatment to
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which rescue therapy they're getting so that we can collect unbiased evidence
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and use causal inference to better understand what the effect of that treatment is.
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And not just that treatment, but the entire treatment sequence.
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And so really for the patient,
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it might not be too different than a standard trial because we're going to treat you over the course of your care.
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But to the investigators, we're going to make sure that
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that data is collected for our trial and there might be randomization for the treatment assignment that follows for that patient.
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So, let's think a little bit about how we analyze or what we can learn from those two different approaches.
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So in the first, we randomize at a single point in time, and if the patient doesn't do well,
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they either drop out of the trial or we assign a rescue therapy.
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Whereas in the SMART design, if they require a change in therapy, we actually randomize what we do.
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So what's different about what we can learn from those two different approaches?
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That's right.
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Often in our standard clinical trial, in that one stage where the patient drops out or receives clinician or patient choice therapy,
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we no longer make inference or have any decisions or really robust results about that subsequent treatment or their outcome.
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Whereas in the SMART, by randomizing that individual and continuing to collect that data,
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we will be able to have really robust evidence over the course of care, over the sequence of treatments
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that could have adapted based on their response to allow us
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to give these sequential guidelines to clinicians to treat the patient not just up front at one point in time,
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but over time, and really tailor it to how they're doing, if they responded, if they adhered, if they engaged with that treatment.
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So in a sense, this more closely follows what happens in actual clinical care,
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where we make a series of treatment decisions based on the patient's prior response, but in this case, you're setting it up
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so we can rigorously learn about what is the best next
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thing to do based on what's happened to the patient so far.
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Is that a fair summary?
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Absolutely.
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We are looking at a type of clinical trial that more closely mimics the way in which treatment is practiced.
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And so that we can provide evidence for these treatment strategies
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that adapt to individual's response or patient status in the way that we would actually treat them in practice.
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Let's suppose that a SMART design is run and there's two points at which patients are randomized,
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maybe the initial therapy and then after some defined period of follow -up.
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What does the result look like in the publication that results,
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and how can clinicians utilize the results of the SMART in guiding their own clinical care?
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One of the amazing advantages of a SMART design is
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that it can answer many questions as opposed to just what is the best treatment at one time.
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We can think about what is the best treatment to begin with?
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What is the best subsequent treatment for those who respond?
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What is the best subsequent treatment for those who don't respond?
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And then we can think about that entire sequence of, okay, so what do we start with?
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How do we change?
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When do we change?
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For whom do we change and what treatment do we give them?
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And so we can really get from SMARTS this sequence of treatments adapted to patient response.
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Not only that, we can collect baseline information, so information up front at the start of the trial, and information about the patient and how they're doing with the treatment,
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how they're adhering, how they're engaging, if they're having side effects,
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and use that information to better tailor the treatment assignment to that individual so that after the trial, right, we have all this information.
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And we can look at what are the best sequences of treatments for which particular individuals.
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The fact that the SMART design more closely matches actual clinical care,
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which the sequences of therapies we offer patients is informed by their responses to prior therapies is an obvious advantage.
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But what are some of the limitations or challenges in either the implementation or the interpretation of a SMART clinical trial?
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I think there are a few limitations and also just lack of knowledge of this design and its opportunities that it offers.
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Some of the limitations are that individuals think, oh, now that we have multiple randomizations or multiple assignments in sequence,
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this is now logistically infeasible, or you're going to lose more people if you have to consent multiple times.
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So one thing is that we often just consent once at the beginning of the smart design.
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and we may randomize multiple times.
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Alternatively, you could randomize up front to that sequence that they may follow, whether they respond or do not respond.
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So logistically, this doesn't have to be very difficult.
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We also have lots of technology that helps us with complex trials, if you want to say that it's complex, although it's not.
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Number two is that individuals are worried about bias coming into play from a smart design
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because of these multiple randomizations and the subsequent randomization depending upon patient response or status.
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This is not a concern because we do not compare these treatment pathways or you first get A,
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you respond and you continue versus you first get A, you do not respond and you switch to B.
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We're not going to compare those people.
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We know that they're different.
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One responded and one didn't, and we can have some issues if we do those comparisons.
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We're looking at what we call adaptive interventions or dynamic treatment regimens that include that entire treatment sequence that's adapted.
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So start with A, and if you respond, continue.
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And if you don't, receive B.
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We're going to think about what are the effects of that entire sequence that's tailored to the response.
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Another misconception is that a SMART is an adaptive design.
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Usually a SMART is a fixed design, not an adaptive design, meaning
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that we're not going to use information from patients who have
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been through the trial to change the trial in some way for future patients.
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So we're not going to change randomization probabilities or eligibility criteria based on the information we've gained from the trial thus far.
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What does happen in a SMART is that patients' treatment might change based on their own response.
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So there might be a within -person adaptation, but there's no between -person adaptation.
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And so generally, these aren't adaptive designs.
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Since we're trying to learn more from a clinical trial that's a smart design versus a traditional design
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that just has a single point of randomization, it seems like we might need larger sample sizes to answer the additional questions.
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What are the challenges, if any, with respect to sample size requirements for a smart design?
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If you see pictures of smart designs, they look a little bit intimidating because there's a fair amount of branching that occurs due to these sequential randomizations.
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And often investigators are quite worried that we're going to require thousands of patients.
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The thing is that to size a SMART is just like sizing any other trial.
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And so it's really dependent on the primary aim, which can be similar to a standard one -stage trial and compare,
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for example, the initial treatments.
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Alternatively, the aim can be based on those embedded tailored sequences of treatments or the adaptive interventions.
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And for those perhaps more patients may be required than a standard trial.
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However, this really isn't an apples -to -apples comparison of a SMART design to a standard or traditional one -stage trial.
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As I mentioned before, the questions
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that we can answer in a SMART are much different and many more than we could with a standard design.
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And so perhaps we may need more depending on the primary aim, but we're going to get a lot more information,
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data, robust results, and more practical information that we can use after a smart design.
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In your article, you discuss a study that was performed by Fortney et al that used a smart approach.
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Can you tell us a little bit about what they did, what they found, and how they analyzed their data?
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Sure.
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So in this study, they had a design where individuals were sequentially randomized to better understand some effects of direct
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and indirect telecare.
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And what they did is they answered questions that are sort of more similar to one stage design.
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So they said, okay, so what's the best first thing to start with?
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And then subsequently, what do we do if individuals aren't responding well to that initial treatment or intervention.
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So they haven't yet pieced together that full sequence.
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It seems like that's subsequent analyses for this group in terms of figuring out,
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so what is the best overall sequences of treatment that can adapt to the individuals?
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While they answered those individually, what they could find when they move forward with the analysis of the adaptive intervention is
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that there might be interactions between the initial treatment
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and the subsequent treatment for
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which we can only really quantify in these types of SMART designs as opposed to individual randomized clinical trials.
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And so what they likely will subsequently do is look at
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that sequence of treatment over the course of the trial
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or those adaptive interventions to see if there are any interactions between the first step and the second step.
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I'm Roger Lewis, and I've been speaking with Professor Kelly Kidwell about sequential multiple assignment randomized trials.
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You can find a link to her article in this episode's description.
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This episode was produced by Daniel Musisi at the JAMA Network.
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To follow this and other JAMA Network podcasts, please visit us online at jamanetworkaudio .com.
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Thanks for listening.
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Vocabulário e dicas de fala para esta lição
Esta aula de conversação usa o vídeo “Sequential, Multiple Assignment, Randomized Trial Designs With Dr Kidwell”. As palavras que mais se repetem: treatment, trial, design, smart, patient. Este vídeo tem 103 frases e 2153 palavras para praticar shadowing. A fala dura 13:26. O falante fala em ritmo natural, cerca de 160 palavras por minuto, próximo de uma conversa do dia a dia. 84% das palavras estão entre as 3.000 mais comuns do inglês; vale a pena estudar o restante antes de começar. 18 das 103 frases são perguntas, por isso é um bom treino para a entonação de perguntas e respostas curtas.
Vocabulário principal deste vídeo
15 palavras do vídeo que vale a pena aprender, com pronúncia e significado:
| Palavra | Pronúncia | Significado |
|---|---|---|
| sequence substantivo | /ˈsiː.kwəns/ | sequência |
| assignment substantivo | /əˈsaɪn.mənt/ | designação |
| subsequent adjetivo | /ˈsʌbsɪkwənt/ | subsequente, seguinte |
| adaptive adjetivo | /əˈdæp.tɪv/ | adaptativo |
| adapt verbo | /əˈdæpt/ | adaptar |
| collect verbo | /ˈkɑlɪkt/ | juntar, reunir |
| intervention substantivo | /ɪntɚˈvɛnʃən/ | intervenção |
| robust adjetivo | /ɹəʊˈbʌst/ | robusto |
| tailor substantivo | /ˈteɪlɚ/ | alfaiate |
| rescue verbo | /ˈɹɛs.kjuː/ | resgatar, salvar |
| compare verbo | /kəmˈpɛɚ/ | comparar |
| participant substantivo | /pɑːɹˈtɪsəpənt/ | participante |
| limitation substantivo | /lɪmɪˈteɪʃən/ | limitação |
| assign verbo | /əˈsaɪn/ | designar, atribuir |
| whereas | /(h)wɛɹˈæz/ | enquanto, ao passo que |
Phrasal verbs que você vai ouvir
| Palavra | Pronúncia | Significado |
|---|---|---|
| go ahead verbo | /ˌɡoʊ əˈhɛd/ | vai em frente |
| figure out verbo | descobrir, deduzir |
Frases que vale a pena repetir
Frases curtas e completas do vídeo que você pode usar na conversa do dia a dia:
- Let's try to break it up a little bit.
- One is that we're interested in sequences of treatments.
- We can think about what is the best treatment to begin with?
- How do we change?
- When do we change?
Gramática neste vídeo
As estruturas que o falante mais usa, com as palavras exatas do vídeo:
| Estrutura | No vídeo |
|---|---|
| Voz passiva be + particípio passado — o foco está no que acontece, não em quem faz | will be randomized · could be assigned · are assigned |
| Orações relativas who / which + oração — informação extra sobre uma pessoa ou coisa | those who respond · those who don · aim, which can |
Pronúncia para ficar de olho
O falante usa 44 contrações e formas reduzidas, como we're, they're, I'm. Diga-as na forma curta, do jeito que você ouve.
- Os sons de “sh” e “zh”: intervention /ɪntɚˈvɛnʃən/, limitation /lɪmɪˈteɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, adaptation /ˌæd.æpˈteɪ.ʃən/, contrast /kənˈt(ʃ)ɹæst/
- Palavras longas — acerte a sílaba tônica: intervention /ɪntɚˈvɛnʃən/, participant /pɑːɹˈtɪsəpənt/, limitation /lɪmɪˈteɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, subsequently /ˈsʌb.sɪ.kwənt.li/
Sons difíceis para falantes de português:
- Consoante final — sem acrescentar um “i” depois: assignment /əˈsaɪn.mənt/, subsequent /ˈsʌbsɪkwənt/, adapt /əˈdæpt/, collect /ˈkɑlɪkt/, robust /ɹəʊˈbʌst/
- /l/ final — a língua toca o céu da boca, não vira “u”: practical /ˈpɹæk.tɪ.kəl/, statistical /stəˈtɪs.tɪ.kəl/, sequential /səˈkwɛntʃəl/, causal /ˈkɔːzəl/
- /h/ — um sopro suave, diferente do “r”: whereas /(h)wɛɹˈæz/, adhere /ædˈhɪə/
Como praticar com este vídeo
- Ouça o vídeo inteiro uma vez sem falar e anote as palavras que você não conhece.
- Comece na velocidade 0,75×, faça shadowing frase por frase e volte à velocidade normal quando ficar fácil.
- Grave a sua voz e compare com o original, prestando atenção a palavras como sequence, assignment, subsequent.
O que é a Técnica de Shadowing?
Shadowing é uma técnica de aprendizado de idiomas com base científica, originalmente desenvolvida para o treinamento de intérpretes profissionais. O método é simples, mas poderoso: você ouve áudio em inglês nativo e repete imediatamente em voz alta — como uma sombra seguindo o falante com 1-2 segundos de atraso. Pesquisas mostram melhora significativa na precisão da pronúncia, entonação, ritmo, sons conectados, compreensão auditiva e fluência na fala.