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Redundant systematic reviews on the same topic in surgery: a study protocol for a meta-epidemiological investigation
  1. Morihiro Katsura1,
  2. Akira Kuriyama2,
  3. Masafumi Tada3,
  4. Kazumichi Yamamoto4,
  5. Toshi A Furukawa3
  1. 1 Department of Surgery, Okinawa Prefectural Miyako Hospital, Okinawa, Japan
  2. 2 Department of General Medicine, Kurashiki Central Hospital, Kurashiki, Japan
  3. 3 Department of Health Promotion and Human Behaviour, Kyoto University Graduate School of Medicine and Public Health, Kyoto, Japan
  4. 4 Department of Ear, Nose and Throat, Komatsu Hospital, Osaka, Japan
  1. Correspondence to Professor Toshi A Furukawa; furukawa{at}


Introduction We are witnessing an explosive increase in redundant and overlapping publications of systematic reviews and meta-analyses (SRs/MAs) on the same topic, which often present conflicting results and interpretations, in the current medical literature. They represent wasted efforts on the part of investigators and peer reviewers and may confuse and possibly mislead clinicians and policymakers. Here, we present a protocol for a meta-epidemiological investigation to describe how often there are overlapping SRs/MAs on the same topic, to assess the quality of these multiple publications, and to investigate the causes of discrepant results between multiple SRs/MAs in the field of major surgery.

Methods and analysis We will use MEDLINE/PubMed to identify all SRs/MAs of randomised controlled trials (RCTs) published in 2015 regarding major surgical interventions. After identifying the ‘benchmark’ SRs/MAs published in 2015, a process of screening in MEDLINE will be carried out to identify the previous SRs/MAs of RCTs on the same topic that were published within 5 years of the ‘benchmark’ SRs/MAs. We will tabulate the number of previous SRs/MAs on the same topic of RCTs, and then describe their variations in numbers of RCTs included, sample sizes, effect size estimates and other characteristics. We will also assess the differences in quality of each SR/MA using A Measurement Tool to Assess Systematic Reviews (AMSTAR) score. Finally, we will investigate the potential reasons to explain the discrepant results between multiple SRs/MAs.

Ethics and dissemination No formal ethical approval and informed consent are required because this study will not collect primary individual data. The intended audiences of the findings include clinicians, healthcare researchers and policymakers. We will publish our findings as a scientific report in a peer-reviewed journal.

Trial registration number In PROSPERO CRD42017059077, March 2017.

  • meta-analysis
  • systematic review
  • same topic
  • overlapping
  • surgical Intervention

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:

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  • Contributors MK, AK and TAF contributed to the conception and design of the research. MK, AK, MT, KY and TAF contributed to the development of the protocol. MK drafted the manuscript. AK and TAF critically reviewed the manuscript for important intellectual content and all authors read and approved the final protocol.

  • Competing interests TAF has received lecture fees from Eli Lilly, Janssen, Meiji, MSD, Otsuka, Pfizer and Tanabe-Mitsubishi, and consultancy fees from Takeda Science Foundation; has received royalties from Igaku-Shoin and Nihon Bunka Kagaku-sha publishers; has received research support from Mochida and Tanabe-Mitsubishi. The other authors declare no competing interests.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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