Citation analysis did not provide a reliable assessment of core outcome set uptake.
OBJECTIVE
The aim of the study was to evaluate citation analysis as an approach to measuring core outcome set (COS) uptake, by assessing whether the number of citations for a COS report could be used as a surrogate measure of uptake of the COS by clinical trialists.


METHODS
Citation data were obtained for COS reports published before 2010 in five disease areas (systemic sclerosis, rheumatoid arthritis, eczema, sepsis and critical care, and female sexual dysfunction). Those publications identified as a report of a clinical trial were examined to identify whether or not all outcomes in the COS were measured in the trial.


RESULTS
Clinical trials measuring the relevant COS made up a small proportion of the total number of citations for COS reports. Not all trials citing a COS report measured all the recommended outcomes. Some trials cited the COS reports for other reasons, including the definition of a condition or other trial design issues addressed by the COS report.


CONCLUSIONS
Although citation data can be readily accessed, it should not be assumed that the citing of a COS report indicates that a trial has measured the recommended COS. Alternative methods for assessing COS uptake are needed.
MRC North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Block F Waterhouse Building, 1-5 Brownlow Street, Liverpool L69 3GL, United Kingdom. Electronic address: Karen.Barnes@liverpool.ac.uk.
Karen L
KL
Barnes
MRC North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Block F Waterhouse Building, 1-5 Brownlow Street, Liverpool L69 3GL, United Kingdom.
Jamie J
JJ
Kirkham
Centre for Public Health, Institute of Clinical Sciences, School of Medicine, Dentistry and Biomedical Sciences, Block B, Queen's University Belfast, Royal Victoria Hospital, Grosvenor Road, Belfast BT12 6BA, United Kingdom.
Mike
M
Clarke
MRC North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Block F Waterhouse Building, 1-5 Brownlow Street, Liverpool L69 3GL, United Kingdom.
Paula R
PR
Williamson
D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D006801:Humans; D055811:Journal Impact Factor; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000706:statistics & numerical data*; D015203:Reproducibility of Results
Citation analysis; Clinical trials; Core outcome set; Eczema; Female sexual dysfunction; Rheumatoid arthritis; Sepsis and critical care; Systemic sclerosis; Uptake