Evidence map›Paper›PMID 38698429›Full record

Observational studySystematic reviews2024

Comparative analysis of Cochrane and non-Cochrane reviews over three decades.

Mikkel Zola Andersen, Philine Zeinert, Jacob Rosenberg, Siv Fonnes

Abstract readComparative StudyObservational Study
In one paragraph

Observational study in Systematic reviews, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
10citing 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

10 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
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  4. Review
  5. Article
  6. Article
  7. Review
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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

4 authors.

Mikkel Zola AndersenCenter for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Borgmester Ib Juuls Vej 1, Herlev, 2730, Denmark. mikkelzola@gmail.com.ORCID 0000-0002-8437-9454
Philine ZeinertCopenhagen University Library, Royal Danish Library, Søren Kierkegaards Plads 1, Copenhagen K, 1221, Denmark.
Jacob RosenbergCenter for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Borgmester Ib Juuls Vej 1, Herlev, 2730, Denmark.
Siv FonnesCenter for Perioperative Optimization, Department of Surgery, Herlev and Gentofte Hospitals, University of Copenhagen, Borgmester Ib Juuls Vej 1, Herlev, 2730, Denmark.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundSystematic reviews are viewed as the best study design to guide clinical decision-making as they are the least biased publications assuming they are well-conducted and include well-designed studies. Cochrane was initiated in 1993 with an aim of conducting high-quality systematic reviews. We aimed to examine the publication rates of non-Cochrane systematic reviews (henceforth referred to simply as "systematic reviews") and Cochrane reviews produced throughout Cochrane's existence and characterize changes throughout the period.

methodsThis observational study collected data on systematic reviews published between 1993 and 2022 in PubMed. Identified Cochrane reviews were linked to data from the Cochrane Database of Systematic Reviews via their Digital Object Identifier. Systematic reviews and Cochrane reviews were analyzed separately. Two authors screened a random sample of records to validate the overall sample, providing a precision of 98%.

resultsWe identified 231,602 (94%) systematic reviews and 15,038 (6%) Cochrane reviews. Publication of systematic reviews has continuously increased with a median yearly increase rate of 26%, while publication of Cochrane reviews has decreased since 2015. From 1993 to 2002, Cochrane reviews constituted 35% of all systematic reviews in PubMed compared with 3.5% in 2013-2022. Systematic reviews consistently had fewer authors than Cochrane reviews, but the number of authors increased over time for both. Chinese first authors conducted 15% and 4% of systematic reviews published from 2013-2022 and 2003-2012, respectively. Most Cochrane reviews had first authors from the UK (36%). The native English-speaking countries the USA, the UK, Canada, and Australia produced a large share of systematic reviews (42%) and Cochrane reviews (62%). The largest publishers of systematic reviews in the last 10 years were gold open access journals.

conclusionsPublication of systematic reviews is increasing rapidly, while fewer Cochrane reviews have been published through the last decade. Native English-speaking countries produced a large proportion of both types of systematic reviews. Gold open access journals and Chinese first authors dominated the publication of systematic reviews for the past 10 years. More research is warranted examining why fewer Cochrane reviews are being published. Additionally, examining these systematic reviews for research waste metrics may provide a clearer picture of their utility.

Indexed as

Systematic Reviews as TopicBibliometricsHumansReview Literature as TopicBibliometricsCochraneEvidence-based medicineInformation scienceSystematic review

Identifiers

PMID38698429
PMCPMC11064235

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.