Fulltext

Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues

Pandis, Nikolaos ; Walsh, Tanya ; Polychronopoulou, Argy ; Eliades, Theodore

In: European Journal of Orthodontics, 2013, vol. 35, no. 5, p. 669-675

Aggiungi alla tua lista
    Titre
    • Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues
    Auteur
    • Pandis, Nikolaos. Private Practice, Corfu, Greece
    • Walsh, Tanya. School of Dentistry, University of Manchester, UK
    • Polychronopoulou, Argy. Department of Community and Preventive Dentistry, School of Dentistry, University of Athens, Greece
    • Eliades, Theodore. Department of Orthodontics and Paediatric Dentistry Center of Dental Medicine, University of Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • European Journal of Orthodontics, 2013, vol. 35, no. 5, p. 669-675. Oxford University Press
    Autre version électronique
    Classification
    • Santé
    Identifiant OAI-PMH
    • oai:doc.rero.ch:291416
    Summary
    Cluster randomized trials (CRTs) use as the unit of randomization clusters, which are usually defined as a collection of individuals sharing some common characteristics. Common examples of clusters include entire dental practices, hospitals, schools, school classes, villages, and towns. Additionally, several measurements (repeated measurements) taken on the same individual at different time points are also considered to be clusters. In dentistry, CRTs are applicable as patients may be treated as clusters containing several individual teeth. CRTs require certain methodological procedures during sample calculation, randomization, data analysis, and reporting, which are often ignored in dental research publications. In general, due to similarity of the observations within clusters, each individual within a cluster provides less information compared with an individual in a non-clustered trial. Therefore, clustered designs require larger sample sizes compared with non-clustered randomized designs, and special statistical analyses that account for the fact that observations within clusters are correlated. It is the purpose of this article to highlight with relevant examples the important methodological characteristics of cluster randomized designs as they may be applied in orthodontics and to explain the problems that may arise if clustered observations are erroneously treated and analysed as independent (non-clustered)