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首页> 外文期刊>Methods of information in medicine >Independence estimating equations for controlled clinical trials with small sample sizes--interval estimation.
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Independence estimating equations for controlled clinical trials with small sample sizes--interval estimation.

机译：小样本量对照临床试验的独立估计方程式-区间估计。

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OBJECTIVES: The application of independence estimating equations (IEE) for controlled clinical trials (CCTs) has recently been discussed, and recommendations for its use have been derived for testing hypotheses. The robust estimator of variance has been shown to be liberal for small sample sizes. Therefore a series of modifications has been proposed. In this paper we systematically compare confidence intervals (CIs) proposed in the literature for situations that are common in CCTs. METHODS: Using Monte-Carlo simulation studies, we compared the coverage probabilities of CIs and non-convergence probabilities for the parameters of the mean structure for small samples using modifications of the variance estimator proposed by Mancl and de Rouen [7], Morel et al. [8] and Pan [3]. RESULTS: None of the proposed modifications behave well in each investigated situation. For parallel group designs with repeated measurements and binary response the method proposed by Pan maintains the nominal level. We observed non-convergence of the IEE algorithm in up to 10% of the replicates depending on response probabilities in the treatment groups. For comparing slopes with continuous responses, the approach of Morel et al. can be recommended. CONCLUSIONS: Results of non-convergence probabilities show that IEE should not be used in parallel group designs with binary endpoints and response probabilities close to 0 or 1. Modifications of the robust variance estimator should be used for sample sizes up to 100 clusters for CI estimation.
机译：目的：最近讨论了独立性估计方程式（IEE）在受控临床试验（CCT）中的应用，并提出了用于测试假设的建议。事实证明，对于小样本量，方差的鲁棒估计量是自由的。因此，提出了一系列修改。在本文中，我们系统地比较了文献中提出的针对CCT中常见情况的置信区间（CI）。方法：使用蒙特卡洛模拟研究，我们使用Mancl和de Rouen [7]提出的方差估计量的修改，比较了小样本平均结构参数的CI的覆盖概率和非收敛概率[7]。 。 [8]和Pan [3]。结果：在每种调查情况下，没有建议的修改方式表现良好。对于具有重复测量和二进制响应的并行组设计，Pan提出的方法保持名义水平。我们观察到IEE算法在多达10％的重复样本中没有收敛，这取决于治疗组中的应答概率。为了比较具有连续响应的斜率，Morel等人的方法。可以推荐。结论：非收敛概率的结果表明，不应将IEE用于二进制端点且响应概率接近0或1的并行组设计中。应将健壮方差估计量的修改用于最多100个聚类的样本，以进行CI估计。 。

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