title: Joint synthesis of multiple correlated outcomes in networks of interventions.
abstract: Multiple outcomes multivariate meta-analysis (MOMA) is gaining in popularity as a tool for jointly synthesizing evidence coming from studies that report effect estimates for multiple correlated outcomes. Models for MOMA are available for the case of the pairwise meta-analysis of two treatments for multiple outcomes. Network meta-analysis (NMA) can be used for handling studies that compare more than two treatments; however, there is currently little guidance on how to perform an MOMA for the case of a network of interventions with multiple outcomes. The aim of this paper is to address this issue by proposing two models for synthesizing evidence from multi-arm studies reporting on multiple correlated outcomes for networks of competing treatments. Our models can handle continuous, binary, time-to-event or mixed outcomes, with or without availability of within-study correlations. They are set in a Bayesian framework to allow flexibility in fitting and assigning prior distributions to the parameters of interest while fully accounting for parameter uncertainty. As an illustrative example, we use a network of interventions for acute mania, which contains multi-arm studies reporting on two correlated binary outcomes: response rate and dropout rate. Both multiple-outcomes NMA models produce narrower confidence intervals compared with independent, univariate network meta-analyses for each outcome and have an impact on the relative ranking of the treatments.
authors.affiliation: Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, 1186 Ioannina 45110, Greece.
authors.forename: Orestis
authors.initials: O
authors.lastname: Efthimiou
authors.affiliation: Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, 1186 Ioannina 45110, GreeceDepartment of Primary Education, University of Ioannina, 1186 Ioannina 45110, Greece.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Mavridis
authors.affiliation: School of Health and Population Sciences, University of Birmingham, Edgbaston, Birmingham, B152TT, UK.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Riley
authors.affiliation: Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, OX37JX, UK WHO Collaborating Centre for Research and Training in Mental Health and Service Evaluation, Department of Public Health and Community Medicine, Section of Psychiatry, University of Verona, Policlinico Giambattista Rossi, Piazzale L.A. Scuro 10, 37134 Verona, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cipriani
authors.affiliation: Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, 1186, Ioannina, 45110, Greece gsalanti@cc.uoi.gr.
authors.forename: Georgia
authors.initials: G
authors.lastname: Salanti
mesh_terms: D001714:Bipolar Disorder / Q000188:drug therapy; D003627:Data Interpretation, Statistical; D006801:Humans; D015201:Meta-Analysis as Topic; D015233:Models, Statistical; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care / Q000379:methods*
keywords: Correlation; Heterogeneity; Mixed-treatment comparison; Multivariate meta-analysis