Mickenautsch Steffen, Yengopal Veerasamy
Faculty of Dentistry, University of the Western Cape, Cape Town, ZAF.
Community Dentistry, University of the Witwatersrand, Johannesburg, ZAF.
Cureus. 2024 Oct 16;16(10):e71668. doi: 10.7759/cureus.71668. eCollection 2024 Oct.
The aim was to test two null hypotheses: that I testing with trial-adjusted simulated comparator trial (SCT) settings does not change the odds of identifying selection bias in clinical trials compared to I testing with generic SCT settings, and that I testing with trial-adjusted SCT settings does not change the odds of identifying selection bias in smaller trials (with sample size (n) = 100-199 per treatment group) compared to larger trials (n > 200 per group).
Baseline data from 67 randomized controlled trials previously tested for selection bias using the I test with generic SCT settings were extracted. The generic settings were: SCT sample size N = 200 (100 for each of Groups A and B), minimum-maximum range of random values (R) = 67 (minimum = 18, maximum = 85), number of generated SCTs used in all meta-analyses (SCT) = 2. The trials were re-tested with trial-adjusted SCT settings. Additionally, the SCT sample sizes were further increased stepwise to N = 400, 800, and 1200, and the resulting I point estimates were recorded. Positive test results (I > 0%) were assigned a score of 1, while negative test results (I = 0%) were assigned a score of 0. From the resulting 0 and 1 scores of both types of SCT settings, odds ratios (ORs) with 95% confidence intervals (CIs) and p-values were computed. The alpha level was set at 5%.
The original I testing with generic SCT settings yielded four positive and 63 negative results. In contrast, testing with trial-adjusted SCT settings of the same trials revealed 13 positive and 54 negative results (OR: 3.79; 95% CI: 1.17 - 12.32; p = 0.03). When the SCT sample size was increased with trial-adjusted SCT settings, the number of positive results rose from 13 to 16 (OR: 1.30; 95% CI: 0.57 - 2.98; p = 0.53). Consequently, only the first null hypothesis was rejected.
I testing with trial-adjusted SCT settings increased the odds of identifying selection bias in clinical trials and did not significantly alter the odds in smaller trials with fewer than 200 patients per intervention group.
本研究旨在检验两个零假设：与使用通用模拟对照试验（SCT）设置进行I检验相比，使用试验调整后的SCT设置进行I检验不会改变在临床试验中识别选择偏倚的概率；与大型试验（每组样本量（n）>200）相比，使用试验调整后的SCT设置进行I检验不会改变在小型试验（每组样本量（n）=100 - 199）中识别选择偏倚的概率。
提取了67项随机对照试验的基线数据，这些试验之前使用通用SCT设置通过I检验进行了选择偏倚检测。通用设置为：SCT样本量N = 200（A组和B组各100），随机值（R）的最小 - 最大范围 = 67（最小值 = 18，最大值 = 85），所有荟萃分析中使用的生成SCT数量（SCT） = 2。使用试验调整后的SCT设置对这些试验重新进行检测。此外，将SCT样本量逐步进一步增加到N = 400、800和1200，并记录所得的I点估计值。阳性检测结果（I>0%）赋值为1，阴性检测结果（I = 0%）赋值为0。根据两种SCT设置所得的0和1分数，计算比值比（OR）及其95%置信区间（CI）和p值。α水平设定为5%。
使用通用SCT设置进行的原始I检验产生了4个阳性结果和63个阴性结果。相比之下，对相同试验使用试验调整后的SCT设置进行检测时，发现有13个阳性结果和54个阴性结果（OR：3.79；95%CI：1.17 - 12.32；p = 0.03）。当使用试验调整后的SCT设置增加SCT样本量时，阳性结果数量从13个增加到16个（OR：1.30；95%CI：0.57 - 2.98；p = 0.53）。因此，仅第一个零假设被拒绝。
使用试验调整后的SCT设置进行I检验增加了在临床试验中识别选择偏倚的概率，并且在每个干预组患者少于200人的小型试验中，该概率没有显著改变。
