Evidence map›Paper›PMID 36773808›Full record

ReviewWorld neurosurgery2023

Surgeon-Specific Treatment Selection Bias and Heterogeneous Perioperative Practices in an Observational Spine Surgery Study. A Statistical Tutorial with Implications for Analysis of Observational Studies of Perioperative Interventions.

Bradley J Hindman, Colin J Gold, Emanuel Ray, Linder H Wendt, Patrick Ten Eyck, Joel I Berger, Catherine R Olinger, Matthew I Banks, Robert D Sanders, Matthew A Howard and 1 more

Open access · greenAbstract readReview
PubMed Full text at PMC Publisher
In one paragraph

Review in World neurosurgery, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.

0numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
1.1field-weighted citation impact, top 22% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

5 citing papers in PubMed, 5 citations in OpenAlex.

  1. Observational
  2. Modified anterior long-segment fixation versus posterior and combined approaches for subaxial cervical fractures in ankylosing spondylitis: a retrospective cohort study.European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society · 2026
    Article
  3. Article
  4. Article
  5. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

11 authors at 3 institutions in 2 countries.

Bradley J HindmanDepartment of Anesthesia, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA. Electronic address: brad-hindman@uiowa.edu.
Colin J GoldDepartment of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
Emanuel RayDepartment of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
Linder H WendtInstitute for Clinical and Translational Science, University of Iowa, Iowa City, Iowa, USA.
Patrick Ten EyckInstitute for Clinical and Translational Science, University of Iowa, Iowa City, Iowa, USA.
Joel I BergerDepartment of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
Catherine R OlingerDepartment of Orthopedics and Rehabilitation, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
Matthew I BanksDepartment of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
Robert D SandersCentral Clinical School and National Health and Medical Research Council (NHMRC) Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia; Department of Anaesthetics and Institute of Academic Surgery, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.
Matthew A HowardDepartment of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
Royce W WoodroffeDepartment of Neurosurgery, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
University of Iowa · USThe University of Sydney · AUUniversity of Wisconsin–Madison · US

Funding

The University of Iowa Clinical and Translational Science AwardUL1TR002537 · NCATS · UNIVERSITY OF IOWA · PI HANSEN, MARLAN R, WINOKUR, PATRICIA · 2018 to 2022
$20.0M
University of Iowa Institute for Clinical and Translational ScienceUM1TR004403 · NCATS · UNIVERSITY OF IOWA · PI Marlan R Hansen, Patricia Winokur · 2023 to 2026
$16.1M
Thalamic and cortical mechanisms of anesthetic-induced unconsciousnessR01GM109086 · NIGMS · UNIVERSITY OF WISCONSIN-MADISON · PI Matthew I Banks, Kirill V Nourski · 2014 to 2026
$5.7M
NCATS NIH HHS UL1 TR002537NCATS NIH HHS UM1 TR004403
6 · The paper itself

Abstract

backgroundIt is essential that treatment effects reported from retrospective observational studies are as reliable as possible. In a retrospective analysis of spine surgery patients, we obtained a spurious result: tranexamic acid (TXA) had no effect on intraoperative blood loss. This statistical tutorial explains how this result occurred and why statistical analyses of observational studies must consider the effects of individual surgeons.

methodsWe used an observational database of 580 elective adult spine surgery patients, supplemented with a review of perioperative medication records. We tested whether common statistical methods (multivariable regression or propensity score-based methods) could adjust for surgeons' selection bias in TXA administration.

resultsBecause TXA administration (frequency, timing, and dose) and surgeon were linked (collinear), estimating and testing the independent effect of TXA on outcome using multivariable regression without including surgeon as a variable would provide biased (spurious) results. Likewise, because of surgeon/TXA linkage, assumptions of propensity score-based analysis were violated, statistical methods to improve comparability between groups failed, and spurious blood loss results were worsened. Others numerous differences among surgeons existed in intraoperative and postoperative practices and outcomes.

conclusionsIn observational studies in which individual surgeons determine whether their patients receive the treatment of interest, consideration must be given to inclusion of surgeon as an independent variable in all analyses. Failure to include the surgeon in an analysis of observational data carries a substantial risk of obtaining spurious results, either creating a spurious treatment effect or failing to detect a true treatment effect.

Indexed as

Antifibrinolytic AgentsSurgeonsTranexamic AcidAdultBlood Loss, SurgicalHumansRetrospective StudiesSelection BiasAntifibrinolytic AgentsTranexamic AcidDeliriumLogistic regressionPropensity scoreSpinal fusionSurgical techniqueTranexamic acid

Identifiers

PMID36773808
PMCPMC12188842
OpenAlexW4319659218

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.