naa a22 4500 530097583 20181026074607.0 cr unu---uuuuu 181026e20180903xx s 000 0 eng 2046-1402 10.12688/f1000research.14770.2 doi (BORIS)oai:boris.unibe.ch:120654 610 ddc 360 ddc 30338058 pmid Estimating the contribution of studies in network meta-analysis: paths, flows and streams [Elektronische Daten] [Theodoros Papakonstantinou, Adriani Nikolakopoulou, Gerta Rücker, Anna Chaimani, Guido Schwarzer, Matthias Egger, Georgia Salanti] publishedVersion openAccess eu-repo In network meta-analysis, it is important to assess the influence of the limitations or other characteristics of individual studies on the estimates obtained from the network. The percentage contribution matrix, which shows how much each direct treatment effect contributes to each treatment effect estimate from network meta-analysis, is crucial in this context. We use ideas from graph theory to derive the percentage that is contributed by each direct treatment effect. We start with the 'projection' matrix in a two-step network meta-analysis model, called the matrix, which is analogous to the hat matrix in a linear regression model. We develop a method to translate entries to percentage contributions based on the observation that the rows of can be interpreted as flow networks, where a stream is defined as the composition of a path and its associated flow. We present an algorithm that identifies the flow of evidence in each path and decomposes it into direct comparisons. To illustrate the methodology, we use two published networks of interventions. The first compares no treatment, quinolone antibiotics, non-quinolone antibiotics and antiseptics for underlying eardrum perforations and the second compares 14 antimanic drugs. We believe that this approach is a useful and novel addition to network meta-analysis methodology, which allows the consistent derivation of the percentage contributions of direct evidence from individual studies to network treatment effects. Papakonstantinou Theodoros joint author Nikolakopoulou Adriani joint author Rücker Gerta joint author Chaimani Anna joint author Schwarzer Guido joint author Egger Matthias joint author Salanti Georgia joint author F1000Research 7, p. 610 2046-1402 https://boris.unibe.ch/120654/1/Papakonstantinou%20F1000Res%202018_rev.pdf text/html WWW-Backlink auf das Repository 1 info:eu-repo/semantics/article boris PeerReviewed boris peerstatus BORIS 856 40 https://boris.unibe.ch/120654/1/Papakonstantinou%20F1000Res%202018_rev.pdf text/html WWW-Backlink auf das Repository BORIS 700 1- Papakonstantinou Theodoros joint author BORIS 700 1- Nikolakopoulou Adriani joint author BORIS 700 1- Rücker Gerta joint author BORIS 700 1- Chaimani Anna joint author BORIS 700 1- Schwarzer Guido joint author BORIS 700 1- Egger Matthias joint author BORIS 700 1- Salanti Georgia joint author BORIS 773 0- F1000Research 7, p. 610 2046-1402 BK010053 XK010053 XK010000 BORIS BORIS BORIS info:eu-repo/semantics/article openAccess