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Review
. 2018 Mar 1;183(suppl_1):124-133.
doi: 10.1093/milmed/usx137.

Utilizing Propensity Score Analyses in Prehospital Blood Product Transfusion Studies: Lessons Learned and Moving Toward Best Practice

Thomas J Greene  1 , Stacia M DeSantis  1 , Erin E Fox  2   3 , Charles E Wade  2   3 , John B Holcomb  2   3 , Michael D Swartz  1   2
Affiliations
Review

Utilizing Propensity Score Analyses in Prehospital Blood Product Transfusion Studies: Lessons Learned and Moving Toward Best Practice

Thomas J Greene et al. Mil Med. .

Abstract

Recently, observational studies analyzing prehospital blood product transfusions (PHT) for trauma have become more widespread in both military and civilian communities. Due to these studies' non-random treatment assignment, propensity score (PS) methodologies are often used to determine an intervention's effectiveness. However, there are no guidelines on how to appropriately conduct PS analyses in prehospital studies. Such analyses are complicated when treatments are given in emergent settings as the ability to administer treatment early, often before hospital admission, can interfere with assumptions of PS modeling. This study conducts a systematic review of literature from military and civilian populations to assess current practice of PS methodology in PHT analyses. The decision-making process from the multicenter Prehospital Resuscitation on Helicopter Study (PROHS) is discussed and used as a motivating example. Results show that researchers often omit or incorrectly assess variable balance between treatment groups and include inappropriate variables in the propensity model. When used correctly, PS methodology is an effective statistical technique to show that aggressive en route resuscitation strategies, including PHT, can reduce mortality in individuals with severe trauma. This review provides guidelines for best practices in study design and analyses that will advance trauma care.

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Figures

Figure 1.
Figure 1.
The medium gray area represents the area of common support (overlap). An example of good overlap is displayed in panel (A) and poor overlap is displayed in panel (B).
Figure 2.
Figure 2.
PRISMA flowchart of search strategy and study selection. Note. PHT, prehospital blood product transfusion.
Figure 3.
Figure 3.
Forest plot of point estimates and variability of the effect of PHT on mortality endpoints for the six selected studies. 1Patients treated with prehospital crystalloid not prehospital blood product transfusion. *Subset of patients without prehospital hypotension. **Subset of patients with prehospital hypotension.
Figure 4.
Figure 4.
Detailed suggested steps for implementing a propensity score analysis with prehospital intervention.
See this image and copyright information in PMC

References

    1. Baraniuk S, Tilley BC, Del Junco DJ, et al. : Pragmatic randomized optimal platelet and plasma ratios (PROPPR) trial: design, rationale and implementation. Injury 2014; 45(9): 1287–95. - PMC - PubMed
    1. Holcomb JB, Tilley BC, Baraniuk S, et al. : Transfusion of plasma, platelets, and red blood cells in a 1: 1: 1 vs a 1: 1: 2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial. JAMA 2015; 313(5): 471–82. - PMC - PubMed
    1. Rosenbaum PR, Rubin DB: The central role of the propensity score in observational studies for causal effects. Biometrika 1983; 70(1): 41–55.
    1. Rubin DB: Estimating causal effects of treatments in randomized and nonrandomized studies. J Educ Psychol 1974; 66(5): 688–701.
    1. Holcomb JB, Swartz MD, DeSantis SM, et al. : Multicenter observational prehospital resuscitation on helicopter study (PROHS). J Trauma Acute Care Surg 2017; 83(1): S83–91. - PMC - PubMed

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