Three-dimensional evidence network plot system: covariate imbalances and effects in network meta-analysis explored using a new software tool.
OBJECTIVE
The aim of the study was to develop the three-dimensional (3D) evidence network plot system-a novel web-based interactive 3D tool to facilitate the visualization and exploration of covariate distributions and imbalances across evidence networks for network meta-analysis (NMA).


METHODS
We developed the 3D evidence network plot system within an AngularJS environment using a third party JavaScript library (Three.js) to create the 3D element of the application. Data used to enable the creation of the 3D element for a particular topic are inputted via a Microsoft Excel template spreadsheet that has been specifically formatted to hold these data. We display and discuss the findings of applying the tool to two NMA examples considering multiple covariates. These two examples have been previously identified as having potentially important covariate effects and allow us to document the various features of the tool while illustrating how it can be used.


RESULTS
The 3D evidence network plot system provides an immediate, intuitive, and accessible way to assess the similarity and differences between the values of covariates for individual studies within and between each treatment contrast in an evidence network. In this way, differences between the studies, which may invalidate the usual assumptions of an NMA, can be identified for further scrutiny. Hence, the tool facilitates NMA feasibility/validity assessments and aids in the interpretation of NMA results.


CONCLUSIONS
The 3D evidence network plot system is the first tool designed specifically to visualize covariate distributions and imbalances across evidence networks in 3D. This will be of primary interest to systematic review and meta-analysis researchers and, more generally, those assessing the validity and robustness of an NMA to inform reimbursement decisions.
Systematic Review Team, DRG Abacus, 6 Talisman Business Centre, Talisman Road, Bicester OX26 6HR, UK. Electronic address: SBatson@teamDRG.com.
Sarah
S
Batson
Systematic Review Team, DRG Abacus, 6 Talisman Business Centre, Talisman Road, Bicester OX26 6HR, UK.
Robert
R
Score
Department of Health Sciences, University of Leicester, Centre for Medicine, University Road, Leicester LE1 7RH, UK.
Alex J
AJ
Sutton
D003196:Computer Graphics; D003627:Data Interpretation, Statistical; D006801:Humans; D012984:Software; D000071076:Network Meta-Analysis as Topic
Covariate; Evidence networks; Heterogeneity; Meta-analysis feasibility; Network meta-analysis; Novel graphical tool; Three dimensional