Mapping the characteristics, methodological quality and standards of reporting of network meta-analyses on antithrombotic therapies: An overview

Background: Although a large number of network meta-analyses (NMAs) in the field of cardiology are available, little is known about their methodological quality. We aimed to map the characteristics and critically appraised the standards of conduct and evidence reporting of NMAs assessing antithrombotic therapies for the treatment or prophylaxis of heart diseases and cardiac surgical procedures.

Methods: We systematically searched PubMed and Scopus to identify NMAs comparing the clinical effects of antithrombotic therapies. Overall characteristics of the NMAs were extracted and their reporting quality and methodological quality were evaluated using the PRISMA-NMA checklist and AMSTAR-2, respectively.

Results: We found 86 NMAs published between 2007 and 2022. Comparisons among direct-acting oral anticoagulants were available in 61 (71%) NMAs. Although around 75% of NMAs stated that they followed international guidelines for conduct and reporting, only one third provided a protocol/register. Complete search strategies and publication bias assessment were lacking in around 53% and 59% of studies, respectively. Most NMAs (n = 77, 90%) provided supplemental material; however, only 5 (6%) made the complete raw data available. Network diagrams were depicted in most studies (n = 67, 78%), yet network geometry was described in only 11 (12.8%) of them. Mean adherence to the PRISMA-NMA checklist was 65.1 ± 16.5%. AMSTAR-2 assessment showed 88% of the NMAs had critically low methodological quality.

Conclusion: Although there is a wide diffusion of NMA-type studies on antithrombotics for heart diseases, their methodological and reporting quality remains suboptimal. This may reflect fragile clinical practices due to misleading conclusions from critically low-quality NMAs.