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Are Japanese randomized controlled trials up to the task? A systematic review
Daisuke Yoneoka1, Akinori Hisashige2, Erika Ota1
1Department of Global Health Policy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
Plos One
|March 6, 2014
Summary
Japanese randomized controlled trials (RCTs) show variable quality, with many lacking funding information and registration. High-quality, non-indexed RCTs exist, highlighting the need for better trial transparency and quality control in Japan.
Area of Science:
- Clinical Trials
- Health Services Research
- Evidence-Based Medicine
Background:
- International databases often miss Japanese randomized controlled trials (RCTs).
- Limited data exists on the quality of RCTs conducted in Japan.
- Assessing Japanese RCTs is crucial for global health research synthesis.
Purpose of the Study:
- To evaluate the characteristics and quality of Japanese RCTs published in 2010.
- To identify factors influencing the quality of these RCTs.
- To address the gap in international databases regarding Japanese clinical trial data.
Main Methods:
- Systematic review of 1013 RCTs published in Japan in 2010.
- Exclusion of study protocols, abstracts, comments, and quasi-RCTs.
- Quality assessment using Cochrane Back Review Group guidelines and logistic regression for factor analysis.
Main Results:
- Most RCTs were small-scale (55% < 50 participants).
- 80% lacked funding disclosure; only 8% were pre-registered.
- 118 RCTs (37.7%) were not indexed internationally, with a moderate proportion being high-quality.
Conclusions:
- Japanese RCT quality is inconsistent, with areas needing improvement.
- High-quality research exists outside major international databases.
- Urgent need for full trial disclosure and enhanced quality control in Japan.
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