Clustering in surgical trials - database of intracluster correlations

Bibliographic Details
Title: Clustering in surgical trials - database of intracluster correlations
Authors: Cook Jonathan A, Bruckner Thomas, MacLennan Graeme S, Seiler Christoph M
Source: Trials, Vol 13, Iss 1, p 2 (2012)
Publisher Information: BMC, 2012.
Publication Year: 2012
Collection: LCC:Medicine (General)
Subject Terms: Surgery, ICC, multicentre, clustering, Medicine (General), R5-920
More Details: Abstract Background Randomised trials evaluation of surgical interventions are often designed and analysed as if the outcome of individual patients is independent of the surgeon providing the intervention. There is reason to expect outcomes for patients treated by the same surgeon tend to be more similar than those under the care of another surgeon due to previous experience, individual practice, training, and infrastructure. Such a phenomenon is referred to as the clustering effect and potentially impacts on the design and analysis adopted and thereby the required sample size. The aim of this work was to inform trial design by quantifying clustering effects (at both centre and surgeon level) for various outcomes using a database of surgical trials. Methods Intracluster correlation coefficients (ICCs) were calculated for outcomes from a set of 10 multicentre surgical trials for a range of outcomes and different time points for clustering at both the centre and surgeon level. Results ICCs were calculated for 198 outcomes across the 10 trials at both centre and surgeon cluster levels. The number of cases varied from 138 to 1370 across the trials. The median (range) average cluster size was 32 (9 to 51) and 6 (3 to 30) for centre and surgeon levels respectively. ICC estimates varied substantially between outcome type though uncertainty around individual ICC estimates was substantial, which was reflected in generally wide confidence intervals. Conclusions This database of surgical trials provides trialists with valuable information on how to design surgical trials. Our data suggests clustering of outcome is more of an issue than has been previously acknowledged. We anticipate that over time the addition of ICCs from further surgical trial datasets to our database will further inform the design of surgical trials.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1745-6215
Relation: http://www.trialsjournal.com/content/13/1/2; https://doaj.org/toc/1745-6215
DOI: 10.1186/1745-6215-13-2
Access URL: https://doaj.org/article/aca88d4f2a0e46ae8a9485e6a2ce36c9
Accession Number: edsdoj.88d4f2a0e46ae8a9485e6a2ce36c9
Database: Directory of Open Access Journals
More Details
ISSN:17456215
DOI:10.1186/1745-6215-13-2
Published in:Trials
Language:English