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Between-trial heterogeneity in meta-analyses may be partially explained by reported design characteristics

OBJECTIVE: We investigated the associations between risk of bias judgments from Cochrane reviews for sequence generation, allocation concealment and blinding, and between-trial heterogeneity. STUDY DESIGN AND SETTING: Bayesian hierarchical models were fitted to binary data from 117 meta-analyses, to...

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Detalles Bibliográficos
Autores principales: Rhodes, Kirsty M., Turner, Rebecca M., Savović, Jelena, Jones, Hayley E., Mawdsley, David, Higgins, Julian P.T.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828111/
https://www.ncbi.nlm.nih.gov/pubmed/29217451
http://dx.doi.org/10.1016/j.jclinepi.2017.11.025
Descripción
Sumario:OBJECTIVE: We investigated the associations between risk of bias judgments from Cochrane reviews for sequence generation, allocation concealment and blinding, and between-trial heterogeneity. STUDY DESIGN AND SETTING: Bayesian hierarchical models were fitted to binary data from 117 meta-analyses, to estimate the ratio λ by which heterogeneity changes for trials at high/unclear risk of bias compared with trials at low risk of bias. We estimated the proportion of between-trial heterogeneity in each meta-analysis that could be explained by the bias associated with specific design characteristics. RESULTS: Univariable analyses showed that heterogeneity variances were, on average, increased among trials at high/unclear risk of bias for sequence generation ([Formula: see text] 1.14, 95% interval: 0.57–2.30) and blinding ([Formula: see text] 1.74, 95% interval: 0.85–3.47). Trials at high/unclear risk of bias for allocation concealment were on average less heterogeneous ([Formula: see text] 0.75, 95% interval: 0.35–1.61). Multivariable analyses showed that a median of 37% (95% interval: 0–71%) heterogeneity variance could be explained by trials at high/unclear risk of bias for sequence generation, allocation concealment, and/or blinding. All 95% intervals for changes in heterogeneity were wide and included the null of no difference. CONCLUSION: Our interpretation of the results is limited by imprecise estimates. There is some indication that between-trial heterogeneity could be partially explained by reported design characteristics, and hence adjustment for bias could potentially improve accuracy of meta-analysis results.