Sinert R, Bright L. Empiric Antibiotic Therapy for Sepsis Patients: Monotherapy With β-Lactam or β-Lactam Plus an Aminoglycoside?
Ann Emerg Med 2008;52:557-560; doi:10.1016/j.annemergmed.2007.12.013
Article Outline
SEE RELATED ARTICLE, P. 557.
Discussion Points
What was the impetus for conducting this meta-analysis? What are the potential drawbacks and advantages of single-versus combined-agent therapy for sepsis? What is the research question of this review?1
Please examine Figure 1 of the article “Causation of Bias: The Episcope,” by Maclure and Schneeweiss (http://www.epidem.com/pt/re/epidemiology/pdfhandler.00001648-200101000-00019.pdf;jsessionid=LngXpLrq9zGx847HMbvqsDsGTGnYM5K4YRzTjghdfb71CCMJTNkJ!-1586968322!181195628!8091!-1?pdfid=/fs028/ovft/live/gv009/00001648/00001648-200101000-00019).2 The figure depicts 10 layers of potential distortion that can render the results of a systematic review a biased estimate of the truth. Briefly discuss how each layer might produce bias in this particular systematic review. Which layers pose the greatest threats? When answering questions 2 to 5, try to identify the relevant layer(s) of the episcope. A. What is the difference between a systematic review and a narrative review? To what does the term “meta-analysis” refer? Why is it important for a systematic review to articulate its search strategy a priori? B. The yield of electronic database searches may be limited even when they are performed by trained medical librarians (Felson DT. Bias in meta-analytic research. J Clin Epidemiol. 1992;45:885-892).3 What techniques did these authors use to ensure that they included as many eligible studies as possible? Referring to the fact that this review includes trials comparing broad-spectrum β-lactams to narrow-spectrum β-lactams (only 20/64 trials used the same β-lactam in both arms), Sinert writes “The ‘apples to oranges limitation' is somewhat ameliorated by the large number of trials reviewed…
.” Do you agree? What do the authors mean by “quasi-randomized” trials? What are the possible pitfalls of including such trials? What elements contributed to the overall “poor” quality of trials in this study? A. Meta-analyses are designed to calculate a summary effect and the relevant confidence interval. Describe the results of this meta-analysis in terms of the summary effect. What are the implications for the use of antibiotics in sepsis?
B. What assumptions are made when study populations are combined and a summary effect is reported? What is the effect of combining studies on the precision of the result? What characteristics of a combined analysis contribute to the change in precision? What is the effect of combining studies on bias? Beginning from the level of the individual published article (level “j” in the figure referenced in question 2),2 describe the further layers of bias that might intervene in this article's presentation of results. The protocol for a systematic review should include descriptions of the following: the research question, methods used for identifying eligible studies, methods of data abstraction, and statistical methods (the meta-analysis). Does the Annals summary of the Cochrane review fully describe all 4 of these components? From a reader's perspective, what are the benefits and limitations of a 4-page summary review of a 117-page review of 64 trials?
References
Editor's Note: You are reading the sixth installment of Annals of Emergency Medicine Journal Club. This bimonthly feature seeks to improve the critical appraisal skills of emergency physicians and other interested readers through a guided critique of actual Annals of Emergency Medicine articles. Each Journal Club will pose questions that encourage readers—be they clinicians, academics, residents, or medical students—to critically appraise the literature.During a 2- to 3-year cycle, we plan to ask questions that cover the main topics in research methodology and critical appraisal of the literature. To do this, we will select articles that use a variety of study designs and analytic techniques. These may or may not be the most clinically important articles in a specific issue, but they are articles that serve the mission of covering the clinical epidemiology curriculum. Journal Club entries are published in 2 phases. In the first phase, a list of questions about the article is published in the issue in which the article appears. Questions are rated “novice,” () “intermediate,” () and “advanced” () so that individuals planning a journal club can assign the right question to the right student. The answers to this journal club will be published in the April 2009 issue. US residency directors will have immediate access to the answers through the Council of Emergency Medicine Residency Directors Share Point Web site. International residency directors can gain access to the questions by going to http://www.emergencymedicine.ucla.edu/annalsjc/ and following the directions. Thus, if a program conducts its journal club within 5 months of the publication of the questions, no one will have access to the published answers except the residency director. The purpose of delaying the publication of the answers is to promote discussion and critical review of the literature by residents and medical students and discourage regurgitation of the published answers.It is our hope that the Journal Club will broaden Annals of Emergency Medicine's appeal to residents and medical students. We are interested in receiving feedback about this feature. Please e-mail journalclub@acep.org with your comments.
PII: S0196-0644(08)01777-0
doi:10.1016/j.annemergmed.2008.09.013
© 2008 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.
Refers to article:
- Empiric Antibiotic Therapy for Sepsis Patients: Monotherapy With β-Lactam or β-Lactam Plus an Aminoglycoside? , 25 February 2008
