IEJ Iranian Endodontic Journal 2014;9(1):56-60 Sample Size Calculation of Clinical Trials Published in Two Leading Endodontic Journals (original) (raw)
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Sample size calculation of clinical trials published in two leading endodontic journals
Iranian endodontic journal, 2014
The purpose of this article was to evaluate the quality of sample size calculation reports in published clinical trials in Journal of Endodontics and International Endodontic Journal in years 2000-1 and 2009-10. Articles fulfilling the inclusion criteria were collected. The criteria were: publication year, research design, types of control group, reporting sample size calculation, the number of participants in each group, study outcome, amount of type I (α) and II (β) errors, method used for estimating prevalence or standard deviation, percentage of meeting the expected sample size and considering clinically importance level in sample size calculation. Data were extracted from all included articles. Descriptive analyses were conducted. Inferential statistical analyses were done using independent T-test and Chi-square test with the significance level set at 0.05. There was a statistically significant increase in years between 2009 and 10 compared to 2000-1 in terms of reporting sampl...
PRIRATE 2020 guidelines for reporting randomized trials in Endodontics: explanation and elaboration
International Endodontic Journal, 2020
Well-designed and properly conducted randomized clinical trials provide a true estimate of the effects of interventions and are acknowledged as the gold standard in terms of clinical study design. However, the quality of randomized clinical trials published in the field of Endodontics is suboptimal. The Preferred Reporting Items for RAndomized Trials in Endodontics (PRIRATE) 2020 guidelines were developed exclusively for Endodontics by integrating and adapting the CONsolidated Standards of Reporting Trials (CONSORT) statement and Clinical and Laboratory Images in Publications (CLIP) principles, through an accepted and well-documented consensus process. Full implementation of the PRIRATE 2020 guidelines will minimize potential sources of bias and thus enhance the standard of manuscripts submitted for publication, which will ultimately improve the reporting of randomized clinical trials in Endodontics. The aim of this document is to provide an explanation for each item in the PRIRATE 2020 checklist and flowchart with examples from the literature in order to help authors understand their rationale and significance. A link to this PRIRATE 2020 explanation and elaboration document is available on the Preferred Reporting Items for study Designs in Endodontology (PRIDE) website at http://www.prideendodonticguidelines.org/prirate/.
Sample size in orthodontic randomized controlled trials: are numbers justified?
The European Journal of Orthodontics, 2013
Sample size calculations are advocated by the Consolidated Standards of Reporting Trials (CONSORT) group to justify sample sizes in randomized controlled trials (RCTs). This study aimed to analyse the reporting of sample size calculations in trials published as RCTs in orthodontic speciality journals. The performance of sample size calculations was assessed and calculations verified where possible. Related aspects, including number of authors; parallel, split-mouth, or other design; singleor multi-centre study; region of publication; type of data analysis (intention-to-treat or per-protocol basis); and number of participants recruited and lost to follow-up, were considered. Of 139 RCTs identified, complete sample size calculations were reported in 41 studies (29.5 per cent). Parallel designs were typically adopted (n = 113; 81 per cent), with 80 per cent (n = 111) involving two arms and 16 per cent having three arms. Data analysis was conducted on an intention-to-treat (ITT) basis in a small minority of studies (n = 18; 13 per cent). According to the calculations presented, overall, a median of 46 participants were required to demonstrate sufficient power to highlight meaningful differences (typically at a power of 80 per cent). The median number of participants recruited was 60, with a median of 4 participants being lost to follow-up. Our finding indicates good agreement between projected numbers required and those verified (median discrepancy: 5.3 per cent), although only a minority of trials (29.5 per cent) could be examined. Although sample size calculations are often reported in trials published as RCTs in orthodontic speciality journals, presentation is suboptimal and in need of significant improvement.
Sample size estimation: An overview with applications to orthodontic clinical trial designs
American Journal of Orthodontics and Dentofacial Orthopedics, 2011
Proper sample size estimation is an important part of clinical trial methodology and closely related to the precision and power of the trial's results. Trials with sufficient sample sizes are scientifically and ethically justified and more credible compared with trials with insufficient sizes. Planning clinical trials with inadequate sample sizes might be considered as a waste of time and resources, as well as unethical, since patients might be enrolled in a study in which the expected results will not be trusted and are unlikely to have an impact on clinical practice. Because of the low emphasis of sample size calculation in clinical trials in orthodontics, it is the objective of this article to introduce the orthodontic clinician to the importance and the general principles of sample size calculations for randomized controlled trials to serve as guidance for study designs and as a tool for quality assessment when reviewing published clinical trials in our specialty. Examples of calculations are shown for 2-arm parallel trials applicable to orthodontics. The working examples are analyzed, and the implications of design or inherent complexities in each category are discussed. (Am J Orthod Dentofacial Orthop 2011;140:e141-e146) a Private practice, Corfu, Greece; visiting assistant professor,
International Endodontic Journal, 2022
High‐quality systematic reviews in the field of Dentistry provide the most definitive overarching evidence for clinicians, guideline developers and healthcare policy makers to judge the foreseeable risks, anticipated benefits, and potential harms of dental treatment. In the process of carrying out a systematic review, it is essential that authors appraise the methodological quality of the primary studies they include, because studies which follow poor methodology will have a potentially serious negative impact on the overall strength of the evidence and the recommendations that can be drawn. In Endodontology, systematic reviews of laboratory studies have used quality assessment criteria developed subjectively by the individual authors as there are no comprehensive, well‐structured, and universally accepted criteria that can be applied objectively and universally to individual studies included in reviews. Unfortunately, these subjective criteria are likely to be inaccurately defined,...
Are Sample Sizes Clear and Justified in RCTs Published in Dental Journals?
PLoS ONE, 2014
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.
Published Endodontic Articles in Pubmed-Indexed Journals from Iran (Editorial)
2012
The aim of this survey was to illustrate statistical information about endodontic research published in pubmed index journals from the different universities of Iran. Materials and Methods: A PubMed search was performed to retrieve the endodontic publications of authors affiliated to different universities of Iran. Abstracts were reviewed and unrelated articles were omitted. Citation of each article was obtained from Scopus and Google scholar databases. Data were extracted and transferred to Microsoft Excel to determine the related scintometric indicators. Results: A total of 307 papers were found according to the defined criteria which shows considerable increase from 2 papers in 1992 to 54 in 2011. The majority of the papers (48%) were related to in vitro studies; this number was 33% for in vivo surveys. Meta-analysis, systematic review and clinical trial constituted 10% of all publications. The average number of authors for the overall publications was 3.84; majority of articles (20%) were written by three authors. The average number of citation from Google Scholar (8.93) was higher than those from Scopus (4.74). Most of the endodontic articles originated from the Mashad University of Medical Sciences (16%). Conclusion: Endodontic publication from different universities in Iran has considerably increased, showing that research is becoming more important.
Estimation of sample size in dental research
International Dental & Medical Journal of Advanced Research - VOLUME 2015, 2015
Sample size determination is an important step while planning a statistical study. The determination of minimum required sample size is extremely important not only for ethical and economic purposes but also to achieve scientifically and statistically sound results. The objective of this article is to emphasize the importance and general principles of sample size calculation for different study designs to produce quality results. This article emphasizes various methods of sample size estimation commonly used in dental research especially formulae method used for simple random sampling. Different formulae are described for comparing different outcome measure (means or proportions) by taking dental data as examples.
Published Endodontic Articles in PubMed-Indexed Journals from Iran
Iranian endodontic journal, 2012
The aim of this survey was to illustrate statistical information about endodontic research published in pubmed index journals from the different universities of Iran. A PubMed search was performed to retrieve the endodontic publications of authors affiliated to different universities of Iran. Abstracts were reviewed and unrelated articles were omitted. Citation of each article was obtained from Scopus and Google scholar databases. Data were extracted and transferred to Microsoft Excel to determine the related scintometric indicators. A total of 307 papers were found according to the defined criteria which shows considerable increase from 2 papers in 1992 to 54 in 2011. The majority of the papers (48%) were related to in vitro studies; this number was 33% for in vivo surveys. Meta-analysis, systematic review and clinical trial constituted 10% of all publications. The average number of authors for the overall publications was 3.84; majority of articles (20%) were written by three auth...