Updating systematic reviews published in Chinese: a cross-sectional study

Article type
Authors
Wei D1, Zhang H2, Li L3, Li R2, Chang X4, Fang Z3, Chen Y1, Yang K1
1School of Basic Medical Sciences, Lanzhou University; Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou , China
2The Second Clinical Medical College of Lanzhou University, Lanzhou , China
3School of Basic Medical Sciences, Lanzhou University, Lanzhou , China
4The First Clinical Medical College of Lanzhou University, Lanzhou , China
Abstract
Background: Updating systematic reviews (SR) is a useful solution for reducing the impact of publication bias (or time lag bias) on the results. Nevertheless, the authors of SRs do not keep SRs up to date. Research shows that only 3% of SRs published in peer-reviewed journals and 38% of Cochrane Reviews have been updated. The quantity of SRs published in Chinese is increasing every year. However, there is little study that focuses on whether they are updated.
Objectives: To investigate the current situation regarding the updating of systematic reviews published in Chinese.
Methods: We used the terms 'systematic review', 'meta-analysis', and 'update' to search two electronic databases, WANFANG Data and China National Knowledge Infrastructure (CNKI). Meanwhile, we performed a handsearch of the four Chinese journals with 'evidence-based' in their titles. The previous version of SRs were also identified. Two independent reviewers screened the updating of SRs and extracted the data. The data extracted included publication year and journal, search strategy, etc.
Results: Five updated SRs were included. Of those, three (60%) were published in peer-reviewed journals, and the two (40%) remaining SRs were published as an abstract of conference and an academic dissertation. Only one (20%) SR reported they had updated their own SR. The range of updating period was from one to seven years. The conclusion had changed in one (20%) SR.
Conclusions: A few SRs published in Chinese have been updated; the period between initial publication and updating varies and is generally long. In addition, generally the authors of SRs do not consider updating their own SRs.