Randomized clinical trials in dentistry: Risks of bias, risks of random errors, reporting quality, and methodologic quality over the years 1955-2013

Humam Saltaji; Susan Armijo-Olivo; Greta G Cummings; Maryam Amin; Carlos Flores-Mir

doi:10.1371/journal.pone.0190089

Randomized clinical trials in dentistry: Risks of bias, risks of random errors, reporting quality, and methodologic quality over the years 1955-2013

PLoS One. 2017 Dec 22;12(12):e0190089. doi: 10.1371/journal.pone.0190089. eCollection 2017.

Authors

Humam Saltaji¹, Susan Armijo-Olivo², Greta G Cummings³, Maryam Amin¹, Carlos Flores-Mir¹

Affiliations

¹ School of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
² Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.
³ Faculty of Nursing, University of Alberta, Edmonton, Alberta, Canada.

Abstract

Objectives: To examine the risks of bias, risks of random errors, reporting quality, and methodological quality of randomized clinical trials of oral health interventions and the development of these aspects over time.

Methods: We included 540 randomized clinical trials from 64 selected systematic reviews. We extracted, in duplicate, details from each of the selected randomized clinical trials with respect to publication and trial characteristics, reporting and methodologic characteristics, and Cochrane risk of bias domains. We analyzed data using logistic regression and Chi-square statistics.

Results: Sequence generation was assessed to be inadequate (at unclear or high risk of bias) in 68% (n = 367) of the trials, while allocation concealment was inadequate in the majority of trials (n = 464; 85.9%). Blinding of participants and blinding of the outcome assessment were judged to be inadequate in 28.5% (n = 154) and 40.5% (n = 219) of the trials, respectively. A sample size calculation before the initiation of the study was not performed/reported in 79.1% (n = 427) of the trials, while the sample size was assessed as adequate in only 17.6% (n = 95) of the trials. Two thirds of the trials were not described as double blinded (n = 358; 66.3%), while the method of blinding was appropriate in 53% (n = 286) of the trials. We identified a significant decrease over time (1955-2013) in the proportion of trials assessed as having inadequately addressed methodological quality items (P < 0.05) in 30 out of the 40 quality criteria, or as being inadequate (at high or unclear risk of bias) in five domains of the Cochrane risk of bias tool: sequence generation, allocation concealment, incomplete outcome data, other sources of bias, and overall risk of bias.

Conclusions: The risks of bias, risks of random errors, reporting quality, and methodological quality of randomized clinical trials of oral health interventions have improved over time; however, further efforts that contribute to the development of more stringent methodology and detailed reporting of trials are still needed.

Publication types

Historical Article
Research Support, Non-U.S. Gov't

MeSH terms

Chi-Square Distribution
Dentistry*
History, 20th Century
History, 21st Century
Humans
Logistic Models
Observer Variation*
Randomized Controlled Trials as Topic*
Research Design

Grants and funding

This project is funded by Alberta Innovates - Health Solutions (AIHS) through a Clinician Fellowship Award, the University of Alberta through the Honorary Izaak Walton Killam Memorial Scholarship, and the Women and Children’s Health Research Institute (WCHRI) through the Honorary WCHRI Award. The funders had no role in study design, decision to publish, or preparation of the manuscript.