Retrieval,reporting and methodological characteristics for systematic reviews/meta-analyses of animal models:a meta-epidemiological study

The study aimed to analyze the reporting and methodological quality of systematic reviews(SRs)/meta-analyses(MAs)of animal models to provide references for later studies and avoid the waste of medical resources.EMBASE and MEDLINE databases were searched from inception to November 2017,with no language restriction.Two reviewers selected inclusion dependently and extracted the basic characteristics.Review Manager 5.3,stata 12.0,and SPSS 21 software were used to conduct analyses.A total of 46 SRs/MAs were included.The results showed that the English databases with high retrieval frequency are PubMed/MEDLINE,EMBASE,and Web of Science.67.31%(31/46)of the articles reported the search strategy in the full text or the appendix.65.22%(30/46)reported the literature screening flow diagram,and only 19.57%(9/46)reported the number of works of literature retrieved in each database.60.87%(28/46)illustrated supplement retrieval.Through 2 subgroup analyses,it was found that there were no significant differences in the quality of reports of PRISMA items.But referring to the methodological quality or reporting of PRESS items,SCI was better than that of non-SCI,while there seemed a source of funding to have no significant impact on the methodological quality or the items of PRESS.The results of PRESS,AMSTAR 2,and PRISMA were correlated,and the correlation between PRISMA and AMSTAR 2 was strong.These results demonstrated that search strategies of animal model SRs/MAs are still not enough comprehensive,report specification and methodological quality still need to be ameliorated.To show users the scientificity and rigor of the study,future research should focus on these various guidelines like PRESS,PRISMA,and AMSTAR 2 checklists that have been issued,it can help to increase the value of research and improve the utilization of medical resources.

Trial characteristics and treatment effect estimates in randomized controlled trials of Chinese herbal medicine: A meta-epidemiological study

Background:Previously published meta-epidemiological studies focused on Western medicine have identified some trial characteristics that impact the treatment effect of randomized controlled trials(RCTs).Nevertheless,it remains unclear if similar associations exist in RCTs on Chinese herbal medicine(CHM).Further,Chinese medicine-related characteristics have not been explored yet.Objective:To investigate trial characteristics related to treatment effect estimates on CHM RCTs.Search strategy:This meta-epidemiological study searched 5 databases for systematic reviews on CHM treatment published between January 2011 and July 2021.Inclusion criteria:An eligible systematic review should only include RCTs of CHM and conduct at least one meta-analysis.Data extraction and analysis:Two reviewers independently conducted data extraction on general characteristics of systematic reviews,meta-analyses and included RCTs.They also assessed the risk of bias of RCTs using the Cochrane risk of bias tool.A two-step approach was used for data analyses.The ratio of odds ratios(ROR) and difference in standardized mean differences (dSMD) with 95%confidence interval (CI) were applied to present the difference in effect estimates for binary and continuous outcomes,respectively.Results:Ninety-one systematic reviews,comprising 1338 RCTs were identified.For binary outcomes,RCTs incorporated with syndrome differentiation (ROR:1.23;95%CI:[1.07,1.39]),adopting Chinese medicine formula (ROR:1.19;95%CI:[1.03,1.34]),with low risk of bias on incomplete outcome data (ROR:1.29;95%CI:[1.06,1.52]) and selective outcome reporting (ROR:1.12;95%CI:[1.01,1.24]),as well as a trial size≥100 (ROR:1.23;95%CI:[1.04,1.42]) preferred to show larger effect estimates.As for continuous outcomes,RCTs with Chinese medicine diagnostic criteria (dSMD:0.23;95%CI:[0.06,0.41]),judged as high/unclear risk of bias on allocation concealment (dSMD:-0.70;95%CI:[-0.99,-0.42]),with low risk of bias on incomplete outcome data (dSMD:0.30;95%CI:[0.18,0.43]),conducted at a single center (dSMD:-0.33;95%CI:[-0.61,-0.05]),not using intention-to-treat analysis (dSMD:-0.75;95%CI:[-1.43,-0.07]),and without funding support (dSMD:-0.22;95%CI:[-0.41,-0.02]) tended to show larger effect estimates.Conclusion:This study provides empirical evidence for the development of a specific critical appraisal tool for risk of bias assessments on CHM RCTs.