Randomization in N-of-1 clinical trials: Is it possible to draw causal inferences from single-patient data?

Published on June 30, 2016   43 min

Other Talks in the Series: The Risk of Bias in Randomized Clinical Trials

Other Talks in the Series: Topical Talks

Welcome to this presentation. My name is Patrick Onghena and together with you, I want to look into the question, whether it is possible to draw casual inferences from single-patient data. The answer will turn out to involve the introduction of randomization in N-of-1 clinical trials.
So we'll kick off this presentation by defining our terms. What is an N-of-1 clinical trial? And what do we mean by randomization in N-of-1 clinical trials? After setting the scene, we are ready to answer our main question, demonstrate how we can achieve casual inference, how designs can be classified, and how the computations can be made feasible. We close this presentation with the discussion and general reflection on the current scientific consensus about N-of-1 clinical trials and on the issue of generalizability.
N-of-1 clinical trial is defined as a clinical trial in which only one single patient participates. The purpose of such a trial is to examine the relation between one or more treatments on one hand, and one or more health related outcome variables on the other hand for that particular patient. This examination is carried out by repeatedly introducing and withdrawing the treatment and conducting repeated measurements for the outcome variable or variables of interest. So the N-of-1 part of the term, refers to the number of patients involved, not to the number of observations, which has to be much larger as implied by the definition. N-of-1 clinical trials are used in evidence-based medicine, if the intention is to focus on a single patient or if a large-scale clinical trial is difficult or impossible, for example, for rare diseases, patients with diverse comorbid conditions or patients using concurrent therapies. Also, financial and other practical restrictions may lead the researcher to opt for N-of-1 clinical trial or small series of N-of-1 clinical trials. For a practitioner an N-of-1 clinical trial may also be the only tool available, if no large group trial has been conducted yet for a specific constellation of patient symptom and setting specific characteristics and nonetheless, immediate evidence-based decision and action are needed.

Randomization in N-of-1 clinical trials: Is it possible to draw causal inferences from single-patient data?

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