Clinicians, institutions, and policy makers use results from randomized controlled trials to makedecisions regarding therapeutic interventions for their patients and populations. Knowing the effectthe intervention has on patients in clinical trials is critical for making both individual patient as well aspopulation-based decisions. However, patients in clinical trials do not always adhere to the protocol.Excluding patients from the analysis who violated the research protocol (did not get their intendedtreatment) can have significant implications that impact the results and analysis of a study.

Intention-to-treat analysis is a method for analyzing results in a prospective randomized studywhere all participants who are randomized are included in the statistical analysis and analyzedaccording to the group they were originally assigned, regardless of what treatment (if any) theyreceived. This method allows the investigator (or consumer of the medical literature) to draw accurate(unbiased) conclusions regarding the effectiveness of an intervention. This method preserves thebenefits of randomization, which cannot be assumed when using other methods of analysis.

The risk of bias is increased whenever treatment groups are not analyzed according to the groupto which they were originally assigned. If an intervention is truly effective (truth), an intention-to-treatanalysis will provide an unbiased estimate of the efficacy of the intervention at the level of adherencein the study. This article will review the “intention-to-treat” principle and its converse, “per-protocol”analysis, and illustrate how using the wrong method of analysis can lead to a significantly biasedassessment of the effectiveness of an intervention.

Clinicians, institutions, healthcare networks, and policymakers use outcomes reported in clinical trials as the basis for medical decision-making when managing individual patients or populations. Therefore, the choice of a valid primary endpoint is crucial for randomized controlled trials (RCT) to demonstrate efficacy of new therapies. Recent improvements in treatment, however, have led to a decline in the morbidity and mortality of several common diseases, resulting in a reduction in relevant outcomes that can be used as clinical trial endpoints. Composite endpoints have been used as a solution to maintain the feasibility of RCTs, particularly when facing low event rates, high cost, and long follow-up. However, the benefits of using composite endpoints must be weighed against the risks of misinterpretation by clinicians and policymakers, as incorrect interpretation may have a detrimental effect on patients and populations. This paper defines a composite endpoint, discusses the rationale for its use, and provides a practical approach to interpreting results to aid in medical decision-making.

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The updated American Heart Association (AHA)/American Stroke Association (ASA) Guidelines for the Early Management of Patients with Acute Ischemic Stroke were published in January 2018.1 The purpose of the guidelines is to provide an up-to-date, comprehensive set of recommendations for clinicians caring for adult patients with acute arterial ischemic stroke in a single document. The guidelines detail new and updated recommendations that reflect and incorporate the most recent literature in the evaluation and management of acute ischemic stroke. Some sections of the latest guidelines have sparked debate in the medical community.

Debate with regard to deciding the optimal diagnostic and treatment strategy for patients is healthy and anticipated with the release of new medical literature or recommendations. However, what is somewhat puzzling and unanticipated with the release of these new guidelines is that within two months of their release the AHA/ASA rescinded its recently released guidelines, publishing a “correction” in which several parts of the document have been deleted.2 An action such as this at the guideline level is unprecedented in recent history and has left stakeholders in the medical community somewhat confused as to the rationale for its occurrence. This article will inform the emergency medicine (EM) healthcare professional of the recent correction of the updated stroke guidelines, identify which sections have been removed (deleted), and will provide a brief summary of the pertinent updates (that have not been deleted) to the 2018 stroke guidelines that have particular relevance to the EM community.