Fulltext

Effects of study precision and risk of bias in networks of interventions: a network meta-epidemiological study

Chaimani, Anna ; Vasiliadis, Haris S. ; Pandis, Nikolaos ; Schmid, Christopher H. ; Welton, Nicky J. ; Salanti, Georgia

In: International Journal of Epidemiology, 2013, vol. 42, no. 4, p. 1120-1131

Aggiungi alla tua lista
    Titre
    • Effects of study precision and risk of bias in networks of interventions: a network meta-epidemiological study
    Auteur
    • Chaimani, Anna. Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece, Department of Orthopaedics, School of Medicine, University of Ioannina, Ioannina, Greece, Molecular Cell Biology and Regenerative Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Department of Orthodontics and Dentofacial Orthopedics, Dental School, Medical Faculty, University of Bern, Bern, Switzerland, Private practice, Corfu, Greece, Center for Evidence Based Medicine and Department of Biostatistics, Program in Public Health, Brown University, Providence, RI, USA and School of Social and Community Medicine, University of Bristol, Bristol, UK
    • Vasiliadis, Haris S.. Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece, Department of Orthopaedics, School of Medicine, University of Ioannina, Ioannina, Greece, Molecular Cell Biology and Regenerative Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Department of Orthodontics and Dentofacial Orthopedics, Dental School, Medical Faculty, University of Bern, Bern, Switzerland, Private practice, Corfu, Greece, Center for Evidence Based Medicine and Department of Biostatistics, Program in Public Health, Brown University, Providence, RI, USA and School of Social and Community Medicine, University of Bristol, Bristol, UK
    • Pandis, Nikolaos. Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece, Department of Orthopaedics, School of Medicine, University of Ioannina, Ioannina, Greece, Molecular Cell Biology and Regenerative Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Department of Orthodontics and Dentofacial Orthopedics, Dental School, Medical Faculty, University of Bern, Bern, Switzerland, Private practice, Corfu, Greece, Center for Evidence Based Medicine and Department of Biostatistics, Program in Public Health, Brown University, Providence, RI, USA and School of Social and Community Medicine, University of Bristol, Bristol, UK
    • Schmid, Christopher H.. Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece, Department of Orthopaedics, School of Medicine, University of Ioannina, Ioannina, Greece, Molecular Cell Biology and Regenerative Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Department of Orthodontics and Dentofacial Orthopedics, Dental School, Medical Faculty, University of Bern, Bern, Switzerland, Private practice, Corfu, Greece, Center for Evidence Based Medicine and Department of Biostatistics, Program in Public Health, Brown University, Providence, RI, USA and School of Social and Community Medicine, University of Bristol, Bristol, UK
    • Welton, Nicky J.. Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece, Department of Orthopaedics, School of Medicine, University of Ioannina, Ioannina, Greece, Molecular Cell Biology and Regenerative Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Department of Orthodontics and Dentofacial Orthopedics, Dental School, Medical Faculty, University of Bern, Bern, Switzerland, Private practice, Corfu, Greece, Center for Evidence Based Medicine and Department of Biostatistics, Program in Public Health, Brown University, Providence, RI, USA and School of Social and Community Medicine, University of Bristol, Bristol, UK
    • Salanti, Georgia. Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece, Department of Orthopaedics, School of Medicine, University of Ioannina, Ioannina, Greece, Molecular Cell Biology and Regenerative Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden, Department of Orthodontics and Dentofacial Orthopedics, Dental School, Medical Faculty, University of Bern, Bern, Switzerland, Private practice, Corfu, Greece, Center for Evidence Based Medicine and Department of Biostatistics, Program in Public Health, Brown University, Providence, RI, USA and School of Social and Community Medicine, University of Bristol, Bristol, UK
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • International Journal of Epidemiology, 2013, vol. 42, no. 4, p. 1120-1131. Oxford University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:303636
    Summary
    Background Empirical research has illustrated an association between study size and relative treatment effects, but conclusions have been inconsistent about the association of study size with the risk of bias items. Small studies give generally imprecisely estimated treatment effects, and study variance can serve as a surrogate for study size. Methods We conducted a network meta-epidemiological study analyzing 32 networks including 613 randomized controlled trials, and used Bayesian network meta-analysis and meta-regression models to evaluate the impact of trial characteristics and study variance on the results of network meta-analysis. We examined changes in relative effects and between-studies variation in network meta-regression models as a function of the variance of the observed effect size and indicators for the adequacy of each risk of bias item. Adjustment was performed both within and across networks, allowing for between-networks variability. Results Imprecise studies with large variances tended to exaggerate the effects of the active or new intervention in the majority of networks, with a ratio of odds ratios of 1.83 (95% CI: 1.09,3.32). Inappropriate or unclear conduct of random sequence generation and allocation concealment, as well as lack of blinding of patients and outcome assessors, did not materially impact on the summary results. Imprecise studies also appeared to be more prone to inadequate conduct. Conclusions Compared to more precise studies, studies with large variance may give substantially different answers that alter the results of network meta-analyses for dichotomous outcomes