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Daly, Caitlin H.; Maconachie, Ross; Ades, A. E.; Welton, Nicky J. – Research Synthesis Methods, 2022
Randomised controlled trials of cancer treatments typically report progression free survival (PFS) and overall survival (OS) outcomes. Existing methods to synthesise evidence on PFS and OS either rely on the proportional hazards assumption or make parametric assumptions which may not capture the diverse survival curve shapes across studies and…
Descriptors: Nonparametric Statistics, Randomized Controlled Trials, Evidence, Networks
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Thom, Howard; White, Ian R.; Welton, Nicky J.; Lu, Guobing – Research Synthesis Methods, 2019
Network meta-analysis compares multiple treatments from studies that form a connected network of evidence. However, for complex networks, it is not easy to see if the network is connected. We use simple techniques from graph theory to test the connectedness of evidence networks in network meta-analysis. The method is to build the adjacency matrix…
Descriptors: Networks, Evidence, Meta Analysis, Graphs
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Thom, Howard; López-López, José A.; Welton, Nicky J. – Research Synthesis Methods, 2020
This paper considers the problem in aggregate data meta-analysis of studies reporting multiple competing binary outcomes and of studies using different summary formats for those outcomes. For example, some may report numbers of patients with at least one of each outcome while others may report the total number of such outcomes. We develop a shared…
Descriptors: Risk, Models, Meta Analysis, Patients
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Donegan, Sarah; Dias, Sofia; Tudur-Smith, Catrin; Marinho, Valeria; Welton, Nicky J. – Research Synthesis Methods, 2018
Background: Meta-regression results must be interpreted taking into account the range of covariate values of the contributing studies. Results based on interpolation or extrapolation may be unreliable. In network meta-regression (NMR) models, which include covariates in network meta-analyses, results are estimated using direct and indirect…
Descriptors: Graphs, Networks, Meta Analysis, Regression (Statistics)
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Pedder, Hugo; Boucher, Martin; Dias, Sofia; Bennetts, Margherita; Welton, Nicky J. – Research Synthesis Methods, 2020
Time-course model-based network meta-analysis (MBNMA) has been proposed as a framework to combine treatment comparisons from a network of randomized controlled trials reporting outcomes at multiple time-points. This can explain heterogeneity/inconsistency that arises by pooling studies with different follow-up times and allow inclusion of studies…
Descriptors: Simulation, Randomized Controlled Trials, Meta Analysis, Comparative Analysis
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Pedder, Hugo; Dias, Sofia; Bennetts, Margherita; Boucher, Martin; Welton, Nicky J. – Research Synthesis Methods, 2019
Background: Model-based meta-analysis (MBMA) is increasingly used to inform drug-development decisions by synthesising results from multiple studies to estimate treatment, dose-response, and time-course characteristics. Network meta-analysis (NMA) is used in Health Technology Appraisals for simultaneously comparing effects of multiple treatments,…
Descriptors: Meta Analysis, Guidelines, Drug Therapy, Decision Making
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van Valkenhoef, Gert; Dias, Sofia; Ades, A. E.; Welton, Nicky J. – Research Synthesis Methods, 2016
Network meta-analysis enables the simultaneous synthesis of a network of clinical trials comparing any number of treatments. Potential inconsistencies between estimates of relative treatment effects are an important concern, and several methods to detect inconsistency have been proposed. This paper is concerned with the node-splitting approach,…
Descriptors: Networks, Meta Analysis, Automation, Models
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Donegan, Sarah; Welton, Nicky J.; Tudur Smith, Catrin; D'Alessandro, Umberto; Dias, Sofia – Research Synthesis Methods, 2017
Background: Many reviews aim to compare numerous treatments and report results stratified by subgroups (eg, by disease severity). In such cases, a network meta-analysis model including treatment by covariate interactions can estimate the relative effects of all treatment pairings for each subgroup of patients. Two key assumptions underlie such…
Descriptors: Network Analysis, Meta Analysis, Outcomes of Treatment, Comparative Analysis