Cited by 294Meta-analysis and systematic reviewsAnimal testing and alternativesStatistical Methods in Clinical Trials

The DOI matches its Crossref record; 68 of the 69 references it cites were found in a registry or an index.

The Need for Randomization in Animal Trials: An Overview of Systematic Reviews

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Abstract

BACKGROUND AND OBJECTIVES: Randomization, allocation concealment, and blind outcome assessment have been shown to reduce bias in human studies. Authors from the Collaborative Approach to Meta Analysis and Review of Animal Data from Experimental Studies (CAMARADES) collaboration recently found that these features protect against bias in animal stroke studies. We extended the scope the work from CAMARADES to include investigations of treatments for any condition. METHODS: We conducted an overview of systematic reviews. We searched Medline and Embase for systematic reviews of animal studies testing any intervention (against any control) and we included any disease area and outcome. We included reviews comparing randomized versus not randomized (but otherwise controlled), concealed versus unconcealed treatment allocation, or blinded versus unblinded outcome assessment. RESULTS: Thirty-one systematic reviews met our inclusion criteria: 20 investigated treatments for experimental stroke, 4 reviews investigated treatments for spinal cord diseases, while 1 review each investigated treatments for bone cancer, intracerebral hemorrhage, glioma, multiple sclerosis, Parkinson's disease, and treatments used in emergency medicine. In our sample 29% of studies reported randomization, 15% of studies reported allocation concealment, and 35% of studies reported blinded outcome assessment. We pooled the results in a meta-analysis, and in our primary analysis found that failure to randomize significantly increased effect sizes, whereas allocation concealment and blinding did not. In our secondary analyses we found that randomization, allocation concealment, and blinding reduced effect sizes, especially where outcomes were subjective. CONCLUSIONS: Our study demonstrates the need for randomization, allocation concealment, and blind outcome assessment in animal research across a wide range of outcomes and disease areas. Since human studies are often justified based on results from animal studies, our results suggest that unduly biased animal studies should not be allowed to constitute part of the rationale for human trials.

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Crossref · 10.1371/journal.pone.0098856

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Authors
Hirst, J. A., Howick, J., Aronson, J. K., Roberts, N., Perera, R., Koshiaris, C., & Heneghan, C.
Affiliations
University of Oxford (GB)
Corresponding author
  • Hirst, Jennifer A.
  • Howick, Jeremy
Venue
PLoS ONE
Published
2014-06-06
Volume
9
Issue
6
Pages
e98856
ISSN
1932-6203 (ISSN-L)
OpenAlex
W2037669635
Cited by
294
References
69
Citations by year
2026: 18 · 2025: 25 · 2024: 20 · 2023: 25 · 2022: 28 · 2021: 38 · 2020: 30 · 2019: 21 · 2018: 20 · 2017: 19 · 2016: 32 · 2015: 16 · 2014: 1
FWCI
6.20
Type
journal article
Language
en
Open access
Locations
  • PLoS ONE (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Figshare (submittedVersion, cc-by)
Funders
National Institute for Health and Care Research
Topics
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
  • Health Sciences › Veterinary › Small Animals › Animal testing and alternatives
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
Keywords
randomization, allocation concealment, blinding, animal models, effect size
MeSH terms
Animals, Research Design, Review Literature as Topic, Bias, Animal Experimentation

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