In this edition of the Archives, Evans et al1 examine whether prehospital intubation results in higher rates of ventilator-associated pneumonia (VAP). They use logistic regression to study the impact of their main exposure variable (prehospital intubation) on their primary outcome (VAP). To adjust for other potentially confounding variables, they add multiple other independent variables to their logistic regression model. Evans et al find that prehospital intubation does not confer an increased risk of VAP. This analysis is a nice example of using multiple regression to study the relationship of an exposure and an outcome after adjusting for potentially confounding variables.
Venn diagram of explained variation in multiple regression equation Y = b0 + b1X1 + b2X2 + e. Y represents the total variance of the dependent variable. X1 and X2 are the variances associated with these independent variables. The amount of the Y variance explained by X1 is p and q. Where both variables X1 and X2 overlap (q), the Y variance is explained by both of these independent variables. Thus, the segment p is that part of the Y variance explained only by X1. The error term, e, is that amount of the Y variance not explained by X1 or X2 (the area outside of p, q, and r).
Thank you for submitting a comment on this article. It will be reviewed by JAMA Surgery editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 4
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.