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General medicine
Evaluating the quality of systematic reviews and meta-analyses published on direct oral anticoagulants in the past 5 years
  1. Ali Eshaghpour1,
  2. Allen Li2,
  3. Arshia Pedram Javidan3,4,
  4. Natalie Chen5,
  5. Sarah Yang5,
  6. Mark Andrew Crowther6
  1. 1 Michael G DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
  2. 2 Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
  3. 3 Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
  4. 4 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
  5. 5 Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
  6. 6 Department of Medicine, McMaster University, Hamilton, Ontario, Canada
  1. Correspondence to Mr Ali Eshaghpour, School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada; ali.eshaghpour{at}


Systematic reviews (SRs) have been reported with increasing frequency as a means of collating studies which may have been performed over different period of times, in different geographical areas and by different groups of investigators. As SRs have become more common, quality metrics such as Assessing the Methodological Quality of Systematic Reviews (AMSTAR) have become available for these reviews. AMSTAR is an 11-point checklist that assesses the methodological and reporting quality of a SR. In clinical practice, direct oral anticoagulants (DOACs) have been increasingly used for the treatment and prevention of both venous and arterial thromboembolism. We sought to evaluate the quality of SRs published on DOACs using the AMSTAR criteria. A comprehensive search of Medline, EMBASE and the Cochrane Database of Systematic Reviews from January 2013 to February 2019 was performed. Two reviewers independently screened titles and abstracts and subsequently full texts for eligibility. Data extraction was also completed in duplicate. Categories of extracted data included AMSTAR rating, journal of publication, year of publication, number of studies included in the SR, reporting adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, number of times the paper was cited and journal impact factor. A total of 3729 articles were identified, of which 250 were eligible for analysis. SR quality was highly variable with mean (SD) AMSTAR score of 5.68/11 (2.21). Reporting adherence to PRISMA guideline correlated with a moderate (5–8) or high quality (9–11) (OR=4.19, p<0.01) AMSTAR score. The methodological quality of DOACs was generally rated to be low-moderate, and improved adherence to AMSTAR methodological practices are strongly recommended.

  • protocols & guidelines
  • internal medicine
  • cardiology

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  • AE and AL are joint first authors.

  • AE and AL contributed equally.

  • NC and SY contributed equally.

  • Contributors Conception and design: AE, AL and MC. Analysis and interpretation: AE, AL, APJ, NC, SY and MC. Data collection: AE, AL, NC and SY. Writing the article: AE, AL, APJ, NC, SY and MC. Critical revision of the article: AE, AL, APJ and MC. Final approval of the article: AE, AL, APJ, NC, SY and MC. Statistical analysis: AE, AL and APJ. Overall responsibility: AE, AL, APJ and MC.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests In the last 24 months: MC discloses sitting on a DSMB for Bayer, sitting on advisory boards and/or receiving funding from BMS Canada, Servier Canada and Diagnostica Stago, preparing educational material and/or providing educational presentations for Pfizer, CSL Behring and Diagnostica Stago and individual stock ownership in Alnylam. Additionally, CW discloses having participated in various medicolegal activities relating to thrombosis, anticoagulant drugs or other aspects of hematological practice, and that these activities are bound by confidentiality arrangements. CW holds the Leo Pharma Chair in Thromboembolism research; the funding for this is held in perpetuity at McMaster University and the interest is used to support CW's research activities. No additional authors have any conflicts to declare.

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