Cargando…

Reporting of sample size calculation in randomised controlled trials: review

Objectives To assess quality of reporting of sample size calculation, ascertain accuracy of calculations, and determine the relevance of assumptions made when calculating sample size in randomised controlled trials. Design Review. Data sources We searched MEDLINE for all primary reports of two arm p...

Descripción completa

Detalles Bibliográficos
Autores principales: Charles, Pierre, Giraudeau, Bruno, Dechartres, Agnes, Baron, Gabriel, Ravaud, Philippe
Formato: Texto
Lenguaje:English
Publicado: BMJ Publishing Group Ltd. 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2680945/
https://www.ncbi.nlm.nih.gov/pubmed/19435763
http://dx.doi.org/10.1136/bmj.b1732
_version_ 1782166989500841984
author Charles, Pierre
Giraudeau, Bruno
Dechartres, Agnes
Baron, Gabriel
Ravaud, Philippe
author_facet Charles, Pierre
Giraudeau, Bruno
Dechartres, Agnes
Baron, Gabriel
Ravaud, Philippe
author_sort Charles, Pierre
collection PubMed
description Objectives To assess quality of reporting of sample size calculation, ascertain accuracy of calculations, and determine the relevance of assumptions made when calculating sample size in randomised controlled trials. Design Review. Data sources We searched MEDLINE for all primary reports of two arm parallel group randomised controlled trials of superiority with a single primary outcome published in six high impact factor general medical journals between 1 January 2005 and 31 December 2006. All extra material related to design of trials (other articles, online material, online trial registration) was systematically assessed. Data extracted by use of a standardised form included parameters required for sample size calculation and corresponding data reported in results sections of articles. We checked completeness of reporting of the sample size calculation, systematically replicated the sample size calculation to assess its accuracy, then quantified discrepancies between a priori hypothesised parameters necessary for calculation and a posteriori estimates. Results Of the 215 selected articles, 10 (5%) did not report any sample size calculation and 92 (43%) did not report all the required parameters. The difference between the sample size reported in the article and the replicated sample size calculation was greater than 10% in 47 (30%) of the 157 reports that gave enough data to recalculate the sample size. The difference between the assumptions for the control group and the observed data was greater than 30% in 31% (n=45) of articles and greater than 50% in 17% (n=24). Only 73 trials (34%) reported all data required to calculate the sample size, had an accurate calculation, and used accurate assumptions for the control group. Conclusions Sample size calculation is still inadequately reported, often erroneous, and based on assumptions that are frequently inaccurate. Such a situation raises questions about how sample size is calculated in randomised controlled trials.
format Text
id pubmed-2680945
institution National Center for Biotechnology Information
language English
publishDate 2009
publisher BMJ Publishing Group Ltd.
record_format MEDLINE/PubMed
spelling pubmed-26809452009-05-14 Reporting of sample size calculation in randomised controlled trials: review Charles, Pierre Giraudeau, Bruno Dechartres, Agnes Baron, Gabriel Ravaud, Philippe BMJ Research Objectives To assess quality of reporting of sample size calculation, ascertain accuracy of calculations, and determine the relevance of assumptions made when calculating sample size in randomised controlled trials. Design Review. Data sources We searched MEDLINE for all primary reports of two arm parallel group randomised controlled trials of superiority with a single primary outcome published in six high impact factor general medical journals between 1 January 2005 and 31 December 2006. All extra material related to design of trials (other articles, online material, online trial registration) was systematically assessed. Data extracted by use of a standardised form included parameters required for sample size calculation and corresponding data reported in results sections of articles. We checked completeness of reporting of the sample size calculation, systematically replicated the sample size calculation to assess its accuracy, then quantified discrepancies between a priori hypothesised parameters necessary for calculation and a posteriori estimates. Results Of the 215 selected articles, 10 (5%) did not report any sample size calculation and 92 (43%) did not report all the required parameters. The difference between the sample size reported in the article and the replicated sample size calculation was greater than 10% in 47 (30%) of the 157 reports that gave enough data to recalculate the sample size. The difference between the assumptions for the control group and the observed data was greater than 30% in 31% (n=45) of articles and greater than 50% in 17% (n=24). Only 73 trials (34%) reported all data required to calculate the sample size, had an accurate calculation, and used accurate assumptions for the control group. Conclusions Sample size calculation is still inadequately reported, often erroneous, and based on assumptions that are frequently inaccurate. Such a situation raises questions about how sample size is calculated in randomised controlled trials. BMJ Publishing Group Ltd. 2009-05-12 /pmc/articles/PMC2680945/ /pubmed/19435763 http://dx.doi.org/10.1136/bmj.b1732 Text en © Charles et al 2009 http://creativecommons.org/licenses/by-nc/2.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Charles, Pierre
Giraudeau, Bruno
Dechartres, Agnes
Baron, Gabriel
Ravaud, Philippe
Reporting of sample size calculation in randomised controlled trials: review
title Reporting of sample size calculation in randomised controlled trials: review
title_full Reporting of sample size calculation in randomised controlled trials: review
title_fullStr Reporting of sample size calculation in randomised controlled trials: review
title_full_unstemmed Reporting of sample size calculation in randomised controlled trials: review
title_short Reporting of sample size calculation in randomised controlled trials: review
title_sort reporting of sample size calculation in randomised controlled trials: review
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2680945/
https://www.ncbi.nlm.nih.gov/pubmed/19435763
http://dx.doi.org/10.1136/bmj.b1732
work_keys_str_mv AT charlespierre reportingofsamplesizecalculationinrandomisedcontrolledtrialsreview
AT giraudeaubruno reportingofsamplesizecalculationinrandomisedcontrolledtrialsreview
AT dechartresagnes reportingofsamplesizecalculationinrandomisedcontrolledtrialsreview
AT barongabriel reportingofsamplesizecalculationinrandomisedcontrolledtrialsreview
AT ravaudphilippe reportingofsamplesizecalculationinrandomisedcontrolledtrialsreview