Are sample sizes clear and justified in RCTs published in dental journals?

Koletsi, Despina; Fleming, Padhraig S; Seehra, Jadbinder; Bagos, Pantelis G; Pandis, Nikolaos (2014). Are sample sizes clear and justified in RCTs published in dental journals? PLoS ONE, 9(1), e85949. Public Library of Science 10.1371/journal.pone.0085949

[img]
Preview
Text
Are Sample Sizes Clear.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (372kB) | Preview

Sample size calculations are advocated by the CONSORT group to justify sample sizes in randomized controlled trials (RCTs). The aim of this study was primarily to evaluate the reporting of sample size calculations, to establish the accuracy of these calculations in dental RCTs and to explore potential predictors associated with adequate reporting. Electronic searching was undertaken in eight leading specific and general dental journals. Replication of sample size calculations was undertaken where possible. Assumed variances or odds for control and intervention groups were also compared against those observed. The relationship between parameters including journal type, number of authors, trial design, involvement of methodologist, single-/multi-center study and region and year of publication, and the accuracy of sample size reporting was assessed using univariable and multivariable logistic regression. Of 413 RCTs identified, sufficient information to allow replication of sample size calculations was provided in only 121 studies (29.3%). Recalculations demonstrated an overall median overestimation of sample size of 15.2% after provisions for losses to follow-up. There was evidence that journal, methodologist involvement (OR = 1.97, CI: 1.10, 3.53), multi-center settings (OR = 1.86, CI: 1.01, 3.43) and time since publication (OR = 1.24, CI: 1.12, 1.38) were significant predictors of adequate description of sample size assumptions. Among journals JCP had the highest odds of adequately reporting sufficient data to permit sample size recalculation, followed by AJODO and JDR, with 61% (OR = 0.39, CI: 0.19, 0.80) and 66% (OR = 0.34, CI: 0.15, 0.75) lower odds, respectively. Both assumed variances and odds were found to underestimate the observed values. Presentation of sample size calculations in the dental literature is suboptimal; incorrect assumptions may have a bearing on the power of RCTs.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > School of Dental Medicine > Department of Orthodontics

UniBE Contributor:

Pandis, Nikolaos

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1932-6203

Publisher:

Public Library of Science

Language:

English

Submitter:

Eveline Carmen Schuler

Date Deposited:

01 Dec 2014 08:56

Last Modified:

25 Jan 2017 12:15

Publisher DOI:

10.1371/journal.pone.0085949

PubMed ID:

24465806

BORIS DOI:

10.7892/boris.60621

URI:

https://boris.unibe.ch/id/eprint/60621

Actions (login required)

Edit item Edit item
Provide Feedback