Additional considerations are required when preparing a protocol for a systematic review with multiple interventions

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. The number of systematic reviews that aim to compare multiple interventions using network meta-analysis is increasing. In this paper, we highlight aspects of a standard systematic review protocol that may need modification when multiple interventions are to be compared. Study Design and setting:We take the protocol format suggested by Cochrane for a standard systematic review as our reference, and compare the considerations for a pairwise review with those required for a valid comparison of multiple interventions. We suggest new sections for protocols of systematic reviews including network meta-analyses with a focus on how to evaluate their assumptions. We provide example text from published protocols to exemplify the considerations. Results and Conclusion:Standard systematic review protocols for pairwise meta-analyses need extensions to accommodate the increased complexity of network meta-analysis. Our suggested modifications are widely applicable to both Cochrane and non-Cochrane systematic reviews involving network meta-analyses. Keywords

Effects of oils and solid fats on blood lipids: a systematic review and network meta-analysis

“…This review was registered in PROSPERO International Prospective Register of Systematic Reviews ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=56513 ). The present NMA was planned, conducted, and reported in adherence to standards of quality for reporting NMAs ( 12 , 13 ).…”

Comparative effects of different dietary approaches on blood pressure in hypertensive and pre-hypertensive patients: A systematic review and network meta-analysis

“…york.ac.uk/prospero/, identifier CRD42016049243) and published a priori (Schwingshackl et al 2017a). The present systematic review adheres to the PRISMA guidelines and the corresponding extension for network meta-analyses (Chaimani et al 2017;Hutton et al 2015).…”

Reporting guidance considerations from a statistical perspective: overview of tools to enhance the rigour of reporting of randomised trials and systematic reviews

“…For readers unfamiliar with NMA, the Explanations and Elaborations document also provides educational content on key methodological concepts and illustrative examples of good reporting 41. Recent research42 has put forward a structured set of suggestions for extensions of the standard protocol structure for traditional systematic reviews addressed by PRISMA-P guidance 38…”