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Updated: May 9, 2026

The Adjuvant Efficacy of Angong Niuhuang Pill in the Treatment of Viral Encephalitis: A Meta-Analysis of Randomized Controlled Trials
Published on: April 19, 2024
A case study of pooled-studies publications indicated potential for both valuable information and bias
Kylie J Thaler1, Laura C Morgan, Megan Van Noord
1Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, 3500 Krems, Austria. kylie.thaler@donau-uni.ac.at
Objectives:
Pooled-studies publications (PSPs) present statistical analyses of multiple randomized controlled trials without a systematic literature search or critical appraisal. We explored the characteristics of PSPs and their potential impact on a systematic review (SR).
Study Design And Setting:
We systematically evaluated PSPs excluded from an SR of second-generation antidepressants. We analyzed their basic characteristics, risk of bias, and the effect of new data on review conclusions.
Results:
We identified 57 PSPs containing a median of five trials (range, 2-11) and 1,233 patients (range, 117-2,919). Ninety-six percent of PSPs were industry funded, and 49% of PSPs contained unpublished data. The median number of citations for PSPs was 29 (range, 0-549). Only 7% planned pooling a priori, and 19% combined trials with identical protocols. Fifty-nine percent of PSPs eligible for general efficacy provided no new data. For some subgroups and accompanying symptoms (e.g., anxiety, insomnia, melancholia, fatigue, sex, and race), more than 30% of PSPs presented entirely new data or data that could alter the strength of the evidence available in the SR.
Conclusion:
In this case study, PSPs provided new information on subgroups and secondary outcomes; however, guidance for reviewers and development of a system to assess their susceptibility to bias are required.
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