Evidence map›Paper›PMID 42387607›Full record

ReviewPerioperative medicine (London, England)2026

Definition, analysis, reporting, and interpretation of perioperative bleeding in randomized controlled trials: a methodological systematic review.

Yasaman Mohammadi Kamalabadi, Guangyong Zou, Maha El-Shimy, Natalie Mariam Zitoun, Justyna Bartoszko, Pavel S Roshanov

Abstract readReview
In one paragraph

Review in Perioperative medicine (London, England), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
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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

0 citing papers in PubMed.

No citing paper in PubMed yet.

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

6 authors.

Yasaman Mohammadi KamalabadiDepartment of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Canada. ymoham24@uwo.ca.ORCID https://orcid.org/0009-0009-4019-8190
Guangyong ZouDepartment of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Canada.ORCID http://orcid.org/0000-0001-5773-4185
Maha El-ShimyDepartment of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Canada.ORCID http://orcid.org/0000-0002-0829-5726
Natalie Mariam ZitounLondon Health Sciences Centre, Victoria Hospital, London, Canada.ORCID http://orcid.org/0000-0002-4555-9815
Justyna BartoszkoDepartment of Anesthesia and Pain Management, Sinai Health System, Women's College Hospital, University Health Network, Toronto, ON, Canada.ORCID http://orcid.org/0000-0002-0738-0451
Pavel S RoshanovDepartment of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Canada.ORCID http://orcid.org/0000-0003-3908-1955

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundPerioperative bleeding is a common surgical complication and a frequently used outcome in randomized trials; however, its definition and analysis are not straightforward and have important implications for trial design, statistical power and interpretation of treatment effect. This review aimed to summarize how perioperative bleeding was defined in randomized controlled trials, along with sample size considerations, analytic approaches, and interpretation practices.

methodsOn April 9th, 2025, we systematically searched the CENTRAL database for randomized trials in surgical settings published after January 2024 that evaluated perioperative bleeding as the primary outcome. Two reviewers independently screened and extracted data. Where appropriate, we categorized findings into conceptually similar domains and applied descriptive analysis.

resultsWe included 115 trials reporting 116 primary bleeding outcomes and identified 36 unique definitions, with assessment periods ranging from intraoperative to more than 30 days postoperatively. Volumetric or gravimetric measures were most common (n = 46 [39.6%]), whereas patient-reported events (n = 5 [4.3%]) and clinical management of blood loss (n = 4 [3.4%]) were rare. Most trials reported a sample size calculation based on the primary outcome (n = 90 [78.3%]), but over one-third lacked effect-size justification (n = 34 [37.8%]). Analyses were predominantly parametric (n = 69 [59.5%]), while a few adjusted for baseline covariates (n = 18 [15.6%]). Interpretation in superiority trials relied mainly on statistical significance (n = 49 [47.6%]). Among noninferiority trials, noninferiority was often claimed without prespecified margins (n = 4 [33.3%]).

conclusionPerioperative bleeding outcomes are defined and analyzed with high inconsistency. Standardized outcome definitions and reporting practices are needed in this field to improve trial comparability and clinical relevance.

Indexed as

Blood loss measuresOutcome assessmentOutcome definitionOutcome reportingPerioperative bleedingSurgical bleedingSurgical complications

Identifiers

PMID42387607
PMCPMC13595797

What OpenQuestion holds

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Registered trials

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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.