Evidence map›Paper›PMID 20639294›Full record

SynthesisBMJ (Clinical research ed.)2010

Small study effects in meta-analyses of osteoarthritis trials: meta-epidemiological study.

Eveline Nüesch, Sven Trelle, Stephan Reichenbach, Anne W S Rutjes, Beatrice Tschannen, Douglas G Altman, Matthias Egger, Peter Jüni

Abstract readComparative StudyMeta-Analysis
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in BMJ (Clinical research ed.), 2010. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 260 papers, 133 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
260citing papers in PubMed, 133 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

260 citing papers in PubMed, 133 syntheses or guidelines pooled it.

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200 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

8 authors.

Eveline NüeschInstitute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland.
Sven Trelle
Stephan Reichenbach
Anne W S Rutjes
Beatrice Tschannen
Douglas G Altman
Matthias Egger
Peter Jüni

Funding

Cancer Research UK
6 · The paper itself

Abstract

objectiveTo examine the presence and extent of small study effects in clinical osteoarthritis research.

designMeta-epidemiological study. DATA SOURCES: 13 meta-analyses including 153 randomised trials (41 605 patients) that compared therapeutic interventions with placebo or non-intervention control in patients with osteoarthritis of the hip or knee and used patients' reported pain as an outcome.

methodsWe compared estimated benefits of treatment between large trials (at least 100 patients per arm) and small trials, explored funnel plots supplemented with lines of predicted effects and contours of significance, and used three approaches to estimate treatment effects: meta-analyses including all trials irrespective of sample size, meta-analyses restricted to large trials, and treatment effects predicted for large trials.

resultsOn average, treatment effects were more beneficial in small than in large trials (difference in effect sizes -0.21, 95% confidence interval -0.34 to -0.08, P=0.001). Depending on criteria used, six to eight funnel plots indicated small study effects. In six of 13 meta-analyses, the overall pooled estimate suggested a clinically relevant, significant benefit of treatment, whereas analyses restricted to large trials and predicted effects in large trials yielded smaller non-significant estimates.

conclusionsSmall study effects can often distort results of meta-analyses. The influence of small trials on estimated treatment effects should be routinely assessed.

Indexed as

HumansOsteoarthritis, HipOsteoarthritis, KneePainRandomized Controlled Trials as TopicSample SizeTreatment Outcome

Identifiers

PMID20639294
PMCPMC2905513

What OpenQuestion holds

Textmetadata
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.