Network meta‐analysis of rare events using the Mantel‐Haenszel method

Efthimiou, Orestis; Rücker, Gerta; Schwarzer, Guido; Higgins, Julian P T; Egger, Matthias; Salanti, Georgia

doi:10.1002/sim.8158

Cited by 64 publications

(81 citation statements)

References 45 publications

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“…Network diagrams for all the included studies and for the subsets contributing each outcome will be produced. For dichotomous outcomes of rare events, we will perform a common-effect Mantel-Haenszel NMA 57. For all other outcomes, we will employ a random-effects NMA assuming a single heterogeneity parameter for all comparisons in each network.…”

Section: Methodsmentioning

confidence: 99%

Acute interventions for aggression and agitation in psychosis: study protocol for a systematic review and network meta-analysis

et al. 2019

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IntroductionIndividuals with psychosis may access emergency services due to aggression and agitation. When the de-escalation technique fails to achieve tranquillisation, several pharmacological options are available. However, evidence on which intervention to prefer in terms of efficacy and tolerability to achieve resolution of the acute episode (ie, rapid tranquillisation) of aggression and agitation is currently fragmentary.Methods and analysisWe will include all randomised controlled trials comparing drugs or drug combinations or placebo for aggression or agitation episodes in adult individuals with psychosis. We will include individuals with psychosis (eg, schizophrenia and related disorders, bipolar disorder with psychotic symptoms, psychotic depression) but not substance or medication-induced psychosis or psychosis due to another medical condition. Our primary outcomes are the change in aggression or agitation scores within few hours since the administration of the intervention (efficacy outcome) and the proportion of participants who dropped out due to adverse effects (tolerability outcome). We will retrieve relevant studies from the register of studies of the Cochrane Schizophrenia Group. Also, we will run additional searches on CENTRAL, Embase and PubMed to retrieve potentially eligible studies focusing on other psychiatric diagnoses than those in the schizophrenia spectrum. We will conduct a random-effects network meta-analysis (NMA) for primary and secondary outcomes. In case of rare events of dichotomous outcomes, a common-effect Mantel-Haenszel NMA will be used instead. We will use the surface under the cumulative ranking curve and the mean ranks to rank all available treatments. Local and global methods of evaluation of inconsistency will be employed. Quality of evidence contributing to network estimates of the main outcomes will also be assessed with Confidence in Network Meta-Analysis.Ethics and disseminationThis study does not require ethical approval. We will disseminate our findings by publishing results in a peer-reviewed journal.PROSPERO registration numberCRD42019137945.

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Section: Methodsmentioning

confidence: 99%

Acute interventions for aggression and agitation in psychosis: study protocol for a systematic review and network meta-analysis

et al. 2019

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“…Of note, however, the importance concept allows approximate 'study weights' to be derived also for one-stage pairwise meta-analyses based on a generalized linear model, such as logistic regression, where study weights are not commonly provided. Importances can also be derived from a one-stage approach based on the Mantel-Haenszel method for NMA [26]. We provide an example in Additional File 1.…”

Section: One-stage Network Meta-analysismentioning

confidence: 99%

“…We suggest also removing multi-arm studies that include c, following the 'separate indirect from direct design evidence' (SIDDE) approach suggested by Efthimiou et al [26].…”

Section: One-stage Network Meta-analysismentioning

confidence: 99%

“…Rather, we define importances as ratios of estimated variances from two different NMAs which could be based on any method, including one-stage approaches or specific methods for binary outcomes. In Additional File 1, we show how to use the Mantel-Haenszel (MH) method to estimate importances both in a pairwise meta-analysis and a network meta-analysis using the recently developed MH method for NMA [26]. This works also in a Bayesian framework.…”

Section: Versatility Of the Importance Approachmentioning

confidence: 99%

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The statistical importance of a study for a network meta-analysis estimate

Rücker

Nikolakopoulou

Papakonstantinou

et al. 2020

BMC Med Res Methodol

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Background: In pairwise meta-analysis, the contribution of each study to the pooled estimate is given by its weight, which is based on the inverse variance of the estimate from that study. For network meta-analysis (NMA), the contribution of direct (and indirect) evidence is easily obtained from the diagonal elements of a hat matrix. It is, however, not fully clear how to generalize this to the percentage contribution of each study to a NMA estimate. Methods: We define the importance of each study for a NMA estimate by the reduction of the estimate's variance when adding the given study to the others. An equivalent interpretation is the relative loss in precision when the study is left out. Importances are values between 0 and 1. An importance of 1 means that the study is an essential link of the pathway in the network connecting one of the treatments with another. Results: Importances can be defined for two-stage and one-stage NMA. These numbers in general do not add to one and thus cannot be interpreted as 'percentage contributions'. After briefly discussing other available approaches, we question whether it is possible to obtain unique percentage contributions for NMA. Conclusions: Importances generalize the concept of weights in pairwise meta-analysis in a natural way. Moreover, they are uniquely defined, easily calculated, and have an intuitive interpretation. We give some real examples for illustration.

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“…One-stage network meta-analysis Of note, however, the importance concept allows approximate 'study weights' to be derived also for one-stage pairwise meta-analyses based on a generalized linear model, such as logistic regression, where study weights are not commonly provided. Importances can also be derived from a one-stage approach based on the Mantel-Haenszel method for NMA [26]. We provide an example in Additional File 1.…”

Section: Pairwise Meta-analysismentioning

confidence: 99%

The statistical importance of a study for a network meta-analysis estimate

Rücker

Nikolakopoulou

Papakonstantinou

et al. 2020

Preprint

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Background In pairwise meta-analysis, the contribution of each study to the pooled estimate is given by its weight, which is based on the inverse variance of the estimate from that study. For network meta-analysis (NMA), the contribution of direct (and indirect) evidence is easily obtained from the diagonal elements of a hat matrix. It is, however, not fully clear how to generalize this to the percentage contribution of each study to a NMA estimate.MethodsWe define the importance of each study for a NMA estimate by the reduction of the estimate's variance when adding the given study to the others. An equivalent interpretation is the relative loss in precision when the study is left out. Importances are values between 0 and 1. An importance of 1 means that the study is an essential link of the pathway in the network connecting one of the treatments with another. ResultsImportances can be defined for two-stage and one-stage NMA. These numbers in general do not add to one and thus cannot be interpreted as `percentage contributions'. After briefly discussing other available approaches, we question whether it is possible to obtain unique percentage contributions for NMA. ConclusionsImportances generalize the concept of weights in pairwise meta-analysis in a natural way. Moreover, they are uniquely defined, easily calculated, and have an intuitive interpretation. We give some real examples for illustration.

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Network meta‐analysis of rare events using the Mantel‐Haenszel method

Cited by 64 publications

References 45 publications

Acute interventions for aggression and agitation in psychosis: study protocol for a systematic review and network meta-analysis

Acute interventions for aggression and agitation in psychosis: study protocol for a systematic review and network meta-analysis

The statistical importance of a study for a network meta-analysis estimate

The statistical importance of a study for a network meta-analysis estimate

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