Evidence map›Paper›PMID 34098926›Full record

ArticleBMC surgery2021

Bias estimation in study design: a meta-epidemiological analysis of transcatheter versus surgical aortic valve replacement.

Saerom Youn, Shannon Avery Wong, Caitlin Chrystoja, George Tomlinson, Harindra C Wijeysundera, Chaim M Bell, Anna R Gagliardi, Nancy N Baxter, Julie Takata, Lakhbir Sandhu and 1 more

Abstract read
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In one paragraph

Article in BMC surgery, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed, 1 pooled it
–field-weighted citation impact
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

1 citing paper in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
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.

Saerom YounInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Shannon Avery WongCollege of Medicine and Dentistry, James Cook University, Parkville, QLD, Australia.
Caitlin ChrystojaInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
George TomlinsonInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Harindra C WijeysunderaInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Chaim M BellInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Anna R GagliardiInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Nancy N BaxterInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.
Julie TakataWomen's College Hospital Research Institute (WCRI), Toronto, ON, Canada.
Lakhbir SandhuDepartment of Surgery, University of Toronto, Toronto, Canada.
David Robert UrbachInstitute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada. david.urbach@wchospital.ca.ORCID http://orcid.org/0000-0002-6476-7337

Funding

Canadian Institute of Health Research MOP-136787
6 · The paper itself

Abstract

backgroundPaucity of RCTs of non-drug technologies lead to widespread dependence on non-randomized studies. Relationship between nonrandomized study design attributes and biased estimates of treatment effects are poorly understood. Our purpose was to estimate the bias associated with specific nonrandomized study attributes among studies comparing transcatheter aortic valve implantation with surgical aortic valve replacement for the treatment of severe aortic stenosis.

resultsWe included 6 RCTs and 87 nonrandomized studies. Surgical risk scores were similar for comparison groups in RCTs, but were higher for patients having transcatheter aortic valve implantation in nonrandomized studies. Nonrandomized studies underestimated the benefit of transcatheter aortic valve implantation compared with RCTs. For example, nonrandomized studies without adjustment estimated a higher risk of postoperative mortality for transcatheter aortic valve implantation compared with surgical aortic valve replacement (OR 1.43 [95% CI 1.26 to 1.62]) than high quality RCTs (OR 0.78 [95% CI 0.54 to 1.11). Nonrandomized studies using propensity score matching (OR 1.13 [95% CI 0.85 to 1.52]) and regression modelling (OR 0.68 [95% CI 0.57 to 0.81]) to adjust results estimated treatment effects closer to high quality RCTs. Nonrandomized studies describing losses to follow-up estimated treatment effects that were significantly closer to high quality RCT than nonrandomized studies that did not.

conclusionStudies with different attributes produce different estimates of treatment effects. Study design attributes related to the completeness of follow-up may explain biased treatment estimates in nonrandomized studies, as in the case of aortic valve replacement where high-risk patients were preferentially selected for the newer (transcatheter) procedure.

Indexed as

Aortic Valve StenosisHeart Valve ProsthesisHeart Valve Prosthesis ImplantationTranscatheter Aortic Valve ReplacementAortic ValveHumansRisk FactorsTreatment OutcomeAortic stenosisBiasMeta-epidemiologicalMeta-regressionNon drug health technologiesNonrandomized studiesRandomized controlled trialsSAVRStudy design attributesTAVI

Identifiers

PMID34098926
PMCPMC8186071

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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.