Evidence map›Paper›PMID 18424475›Full record

ArticleInternational journal of epidemiology2008

Sensitivity of between-study heterogeneity in meta-analysis: proposed metrics and empirical evaluation.

Nikolaos A Patsopoulos, Evangelos Evangelou, John P A Ioannidis

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In one paragraph

Article in International journal of epidemiology, 2008. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 592 papers, 150 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
592citing papers in PubMed, 150 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

592 citing papers in PubMed, 150 syntheses or guidelines pooled it.

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  7. Helicobacter pylori Infection and Metabolic Dysfunction-Associated Steatotic Liver Disease: A Prospective Study and Meta-Analysis.Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology · 2026
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  16. Paraspinal muscle quality in chronic low back pain: a systematic review and meta-analysis of muscle atrophy and fat infiltration.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
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532 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

3 authors.

Nikolaos A PatsopoulosClinical Trials and Evidence-Based Medicine Unit and Clinical and Molecular Epidemiology Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina 45110, Greece.
Evangelos Evangelou
John P A Ioannidis

Funding

CARDIOVASCULAR DISEASE PREVENTION TRAINING PROGRAMT32HL007034 · NHLBI · STANFORD UNIVERSITY · PI GARDNER, CHRISTOPHER D · 1985 to 2020
$8.7M
NHLBI NIH HHS T32 HL007034
6 · The paper itself

Abstract

backgroundSeveral approaches are available for evaluating heterogeneity in meta-analysis. Sensitivity analyses are often used, but these are often implemented in various non-standardized ways.

methodsWe developed and implemented sequential and combinatorial algorithms that evaluate the change in between-study heterogeneity as one or more studies are excluded from the calculations. The algorithms exclude studies aiming to achieve either the maximum or the minimum final I(2) below a desired pre-set threshold. We applied these algorithms in databases of meta-analyses of binary outcome and >/=4 studies from Cochrane Database of Systematic Reviews (Issue 4, 2005, n = 1011) and meta-analyses of genetic associations (n = 50). Two I(2) thresholds were used (50% and 25%).

resultsBoth algorithms have succeeded in achieving the pre-specified final I(2) thresholds. Differences in the number of excluded studies varied from 0% to 6% depending on the database and the heterogeneity threshold, while it was common to exclude different specific studies. Among meta-analyses with initial I(2) > 50%, in the large majority [19 (90.5%) and 208 (85.9%) in genetic and Cochrane meta-analyses, respectively] exclusion of one or two studies sufficed to decrease I(2) < 50%. Similarly, among meta-analyses with initial I(2) > 25%, in most cases [16 (57.1%) and 382 (81.3%), respectively) exclusion of one or two studies sufficed to decrease heterogeneity even <25%. The number of excluded studies correlated modestly with initial estimated I(2) (correlation coefficients 0.52-0.68 depending on algorithm used).

conclusionsThe proposed algorithms can be routinely applied in meta-analyses as standardized sensitivity analyses for heterogeneity. Caution is needed evaluating post hoc which specific studies are responsible for the heterogeneity.

Indexed as

AlgorithmsModels, StatisticalDatabases, GeneticHumansMeta-Analysis as TopicTreatment Outcome

Identifiers

PMID18424475
PMCPMC6281381

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.