Evidence map›Paper›PMID 41626891›Full record

ArticleResearch synthesis methods2026

Examining covariate-specific treatment effects in individual participant data meta-analysis: Framing aggregation bias in terms of trial-level confounding and funnel plots.

Lianne K Siegel, Joseph S Koopmeiners, Jamie Hartmann-Boyce, Peter J Godolphin, Abdel G Babiker, Giota Touloumi, Kirk U Knowlton, Richard D Riley

Abstract read
In one paragraph

Article in Research synthesis methods, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–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. 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

8 authors.

Lianne K SiegelDivision of Biostatistics and Health Data Science, School of Public Health, University of Minnesota, Minneapolis, MN, USA.ORCID https://orcid.org/0000-0001-9440-9146
Joseph S KoopmeinersDivision of Biostatistics and Health Data Science, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
Jamie Hartmann-BoyceDepartment of Health Promotion and Policy, School of Public Health & Health Sciences, University of Massachusetts Amherst, Amherst, MA, USA.
Peter J GodolphinMRC Clinical Trials Unit at UCL, University College London, London, UK.ORCID https://orcid.org/0000-0003-0648-0992
Abdel G BabikerMRC Clinical Trials Unit at UCL, University College London, London, UK.
Giota TouloumiDepartment of Hygiene, Epidemiology and Medical Statistics, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
Kirk U KnowltonIntermountain Medical Center, Intermountain Heart Institute, Salt Lake City, UT, USA.
Richard D RileySchool of Health Sciences, University of Birmingham, Birmingham, UK; and National Institute for Health and Care Research (NIHR) Birmingham Biomedical Research Centre, UK.

Funding

Innovative Statistical Methods for Evaluating the Impact of Tobacco Product StandardsR01DA046320 · NIDA · UNIVERSITY OF MINNESOTA · PI Joseph S. Koopmeiners, David M. Vock · 2018 to 2026
$2.4M
National Institute of Allergy and Infectious Diseases 18X107CF6NIDA NIH HHS R01DA046320U.S. National Library of Medicine R01LM012982
6 · The paper itself

Abstract

To understand a treatment's potential impact at the individual level, it is crucial to explore whether the effect differs across patient subgroups and covariate values. Meta-analysis provides an important tool for detecting treatment-covariate interactions, as it can improve power compared to a single study. However, aggregation bias can occur when estimating individual-level treatment-covariate interactions in meta-analysis, due to trial-level confounding. This refers to when the association between the covariate and treatment effect

Indexed as

Meta-Analysis as TopicBiasComputer SimulationConfounding Factors, EpidemiologicCOVID-19Data Interpretation, StatisticalHumansModels, StatisticalResearch DesignSARS-CoV-2Treatment Effect HeterogeneityTreatment Outcomeaggregation biasheterogeneity, individual participant datainteractionsIPDmeta-analysis

Identifiers

PMID41626891
PMCPMC12823212

What OpenQuestion holds

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LicenceCC BY
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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.