Words Matter: Researchers Should Avoid Implying Causation in Studies of Association

I read with interest the article by Spaite et al.1 The authors should be commended for a carefully conducted analysis of the association between survival after major traumatic brain injury and the combination of hypoxia and hypotension. However, even with attempts to statistically isolate hypoxia and hypotension from confounding variables such as injury severity, this nonrandomized cohort study cannot determine causation, which is implied by the title ("The Effect of Combined Out-of-Hospital Hypotension and Hypoxia on Mortality in Major Traumatic Brain Injury"), the abstract, the article, and the Editor's Capsule Summary ("what is the effect on survival of the combination of hypotension and hypoxia compared with either factor alone?").

http://ift.tt/2uc1ID2