Cochrane Iran Associate Centre, National Institute for Medical Research Development (NIMAD), Tehran 1419693111, Iran.
Dental Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran 1983969411, Iran.
Int J Environ Res Public Health. 2021 Jul 7;18(14):7284. doi: 10.3390/ijerph18147284.
To assess the Risk of Bias (RoB) and other characteristics of published randomised clinical trials within Cochrane oral health systematic reviews.
All the published clinical trials within Cochrane oral health systematic reviews until 1 June 2020 were identified and examined. RoB was assessed for all the included clinical trials according to the Cochrane review standards. The Overall Risk of Bias (ORoB) was defined in this study using Cochrane's RoB tool-v2. Descriptive analyses were carried out to determine the frequency of each variable in the study sample.
Out of a total of 2565 included studies, the majority ( = 1600) had sample sizes of 50 or higher. Regarding blinding, 907 studies were labelled as double-blind. Among the various domains of bias, the performance bias showed the highest rate of high risk (31.4%). Almost half of the studies had a high ORoB, compared to 11.1% with a low ORoB. The studies that used placebos had a higher percentage of low ORoB (14.8% vs. 10.7%). Additionally, the double- and triple-blind studies had higher percentages of low ORoB (23.6% and 23.3%, respectively), while the studies with a crossover design had the highest percentage of low ORoB (28.8%).
The RoB of oral health studies published as Cochrane reviews was deemed high.
评估 Cochrane 口腔健康系统评价中已发表的随机临床试验的偏倚风险（RoB）和其他特征。
截至 2020 年 6 月 1 日，检索并评估了所有发表在 Cochrane 口腔健康系统评价中的临床试验。根据 Cochrane 评价标准，对所有纳入的临床试验进行 RoB 评估。本研究使用 Cochrane 的 RoB 工具-v2 定义了总体 RoB（ORoB）。采用描述性分析确定研究样本中每个变量的频率。
在总共 2565 项纳入研究中，大多数（n=1600）的样本量为 50 或更大。关于盲法，907 项研究被标记为双盲。在各种偏倚领域中，实施偏倚的高风险率最高（31.4%）。与低 ORoB（11.1%）相比，近一半的研究存在高 ORoB。使用安慰剂的研究中，低 ORoB 的比例较高（14.8%比 10.7%）。此外，双盲和三盲研究的低 ORoB 比例较高（分别为 23.6%和 23.3%），而交叉设计的研究中低 ORoB 的比例最高（28.8%）。
发表在 Cochrane 评价中的口腔健康研究的 RoB 被认为较高。
