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Updated: Mar 22, 2026
Meta-Analysis of the Effectiveness and Safety of Shugan Jieyu Capsules for the Treatment of Insomnia
Published on: February 17, 2023
A third of systematic reviews changed or did not specify the primary outcome: a PROSPERO register study
Andrea C Tricco1, Elise Cogo2, Matthew J Page3
1Knowledge Translation Program, Li Ka Shing Knowledge Institute, St. Michael's Hospital, 209 Victoria Street, East Building, Toronto, Ontario M5B 1T8, Canada; Epidemiology Division, Dalla Lana School of Public Health, University of Toronto, 155 College Street, 6th Floor, Toronto, Ontario M5T 3M7, Canada.
Objectives:
To examine outcome reporting bias of systematic reviews registered in PROSPERO.
Study Design And Setting:
Retrospective cohort study. The primary outcomes from systematic review publications were compared with those reported in the corresponding PROSPERO records; discrepancies in the primary outcomes were assessed as upgrades, additions, omissions, or downgrades. Relative risks (RRs) and 95% confidence intervals (CI) were calculated to determine the likelihood of having a change in primary outcome when the meta-analysis result was favorable and statistically significant.
Results:
Ninety-six systematic reviews were published. A discrepancy in the primary outcome occurred in 32% of the included reviews and 39% of the reviews did not explicitly specify a primary outcome(s); 6% of the primary outcomes were omitted. There was no significant increased risk of adding/upgrading (RR, 2.14; 95% CI: 0.53, 8.63) or decreased risk of downgrading (RR, 0.76; 95% CI: 0.27, 2.17) an outcome when the meta-analysis result was favorable and statistically significant. As well, there was no significant increased risk of adding/upgrading (RR, 0.89; 95% CI: 0.31, 2.53) or decreased risk of downgrading (RR, 0.56; 95% CI: 0.29, 1.08) an outcome when the conclusion was positive.
Conclusions:
We recommend review authors carefully consider primary outcome selection, and journals are encouraged to focus acceptance on registered systematic reviews.
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