Excerpt from the Limitations section of Fermann et al 2015, Acad Emerg Med. 2015 Mar; 22(3): 299–307 (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4405051/).
Owing to the nature of a post hoc study, any significant values must be interpreted with caution. In the current analysis, no multiple testing was conducted and p-values remain unadjusted. Moreover, a selection bias arising from the randomized open-label design of the original EINSTEIN PE study cannot be ruled out.
Author guidelines published by The Society for Academic Emergency Medicine. (http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1553-2712/homepage/ForAuthors.html)