Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comment
. 2025 Jul 15;29(1):307.
doi: 10.1186/s13054-025-05562-w.

Confused with confounders? Understanding the role of directed acyclic graphs in observational research

Wilson Fandino  1 , Kariem El-Boghdadly  2   3
Affiliations
Comment

Confused with confounders? Understanding the role of directed acyclic graphs in observational research

Wilson Fandino et al. Crit Care. .
No abstract available

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Directed acyclic graph (DAG) for the variables included in the study of Russotto et al. All variables are mediators for this relationship, except for apneic oxygenation
Fig. 2
Fig. 2
Directed acyclic graph (DAG) for some of the variables included in the study of Russotto et al., to estimate the average causal effect of patient’s positioning for intubation on first-attempt intubation success. In this hypothetical scenario, the covariates included can be potential confounders for the association of interest. The relationships between covariates are omitted for clarity
Fig. 3
Fig. 3
A proposed directed acyclic graph (DAG) for the model illustrated in Fig. 1, after accounting for potential confounders. In this theoretical model, the contribution of residual confounding to the obtained estimates is reduced by including a relevant set of observed confounders for the association between body mass index and first-attempt intubation success. ASA: American Society of Anesthesiology
See this image and copyright information in PMC

Comment on

References

    1. Russotto V, Laffey JG, Tassistro E, Myatra SN, Rezoagli E, Foti G, et al. Peri-intubation complications in critically ill obese patients: a secondary analysis of the international INTUBE cohort. Crit Care. 2025;29(1):1–12. - PMC - PubMed
    1. VanderWeele TJ, Shpitser I. On the definition of a confounder. Ann Stat. 2013;41(1):196–220. - PMC - PubMed
    1. Jager KJ, Zoccali C, Macleod A, Dekker FW. Confounding: what it is and how to deal with it. Kidney Int. 2008;73(3):256–60. - PubMed
    1. Pearl J. Causal diagrams for empirical research. Biometrika. 1995;82:669–710.
    1. Zhang Z. Distinguishing between mediators and confounders is important for the causal inference in observational studies. AME Med J, 2019;4.

LinkOut - more resources