The effects of excluding patients from the analysis in randomised controlled trials: meta-epidemiological study.
The effects of excluding patients from the analysis in randomised controlled trials: meta-epidemiological study.
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DOI：
10.1136/bmj.b3244
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发表时间：
2009-09-07
期刊：
影响因子：
--
通讯作者：
Jüni P
中科院分区：
文献类型：
--
作者：
Nüesch E;Trelle S;Reichenbach S;Rutjes AW;Bürgi E;Scherer M;Altman DG;Jüni P
目的探讨将患者排除在随机试验分析之外是否与治疗效果的偏倚估计和试验之间较高的异质性相关。设计基于随机试验荟萃分析的荟萃流行病学研究。数据来源14项荟萃分析，包括167项试验，将髋关节或膝关节骨关节炎患者的治疗干预与安慰剂或非干预对照进行比较，并使用患者报告的疼痛作为结果。方法通过随访结束时各组疼痛强度平均值的差异除以合并标准差计算效应量。采用随机效应荟萃分析对试验进行合并。比较分析中有和没有排除的试验对治疗效果的估计，并评估将荟萃分析限制在没有排除的试验中的影响。结果39项试验（23%）将所有患者纳入分析。在128项试验（77%）中，一些患者被排除在分析之外。排除试验的效应量往往比未排除试验的效应量更有利（差异为- 0.13,95%置信区间为- 0.29至0.04）。然而，个体荟萃分析之间的偏倚估计差异很大（τ2=0.07）。在五项荟萃分析中，分析排除与治疗效果估计之间的相互作用检验为正。分层分析表明，在试验异质性较高的荟萃分析中，在估计治疗获益较大的荟萃分析中，以及在补充医学的荟萃分析中，排除试验和未排除试验之间的效应大小差异更为明显。将荟萃分析限制在没有排除的试验中，导致估计治疗获益较小，P值较大，试验间异质性显著降低。在随机试验中，将患者排除在分析之外往往会导致对治疗效果的偏倚估计，但偏倚的程度和方向是不可预测的。治疗意向分析的结果总是应在随机试验报告中描述。在系统评价中，应定期评估从分析中排除对估计治疗效果的影响。
Objective To examine whether excluding patients from the analysis of randomised trials are associated with biased estimates of treatment effects and higher heterogeneity between trials. Design Meta-epidemiological study based on a collection of meta-analyses of randomised trials. Data sources 14 meta-analyses including 167 trials that compared therapeutic interventions with placebo or non-intervention control in patients with osteoarthritis of the hip or knee and used patient reported pain as an outcome. Methods Effect sizes were calculated from differences in means of pain intensity between groups at the end of follow-up, divided by the pooled standard deviation. Trials were combined by using random effects meta-analysis. Estimates of treatment effects were compared between trials with and trials without exclusions from the analysis, and the impact of restricting meta-analyses to trials without exclusions was assessed. Results 39 trials (23%) had included all patients in the analysis. In 128 trials (77%) some patients were excluded from the analysis. Effect sizes from trials with exclusions tended to be more beneficial than those from trials without exclusions (difference −0.13, 95% confidence interval −0.29 to 0.04). However, estimates of bias between individual meta-analyses varied considerably (τ2=0.07). Tests of interaction between exclusions from the analysis and estimates of treatment effects were positive in five meta-analyses. Stratified analyses indicated that differences in effect sizes between trials with and trials without exclusions were more pronounced in meta-analyses with high between trial heterogeneity, in meta-analyses with large estimated treatment benefits, and in meta-analyses of complementary medicine. Restriction of meta-analyses to trials without exclusions resulted in smaller estimated treatment benefits, larger P values, and considerable decreases in between trial heterogeneity. Conclusion Excluding patients from the analysis in randomised trials often results in biased estimates of treatment effects, but the extent and direction of bias is unpredictable. Results from intention to treat analyses should always be described in reports of randomised trials. In systematic reviews, the influence of exclusions from the analysis on estimated treatment effects should routinely be assessed.
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DOI：
10.1016/0197-2456(86)90046-2
发表时间：
1986-09-01
期刊：
CONTROLLED CLINICAL TRIALS
影响因子：
--
作者：
DERSIMONIAN, R;LAIRD, N
通讯作者：
LAIRD, N
影响因子：
120.7
作者：
Egger, M;J端ni, P;Bartlett, C
通讯作者：
Bartlett, C
影响因子：
105.7
作者：
Fergusson, D;Aaron, SD;Hébert, P
通讯作者：
Hébert, P
影响因子：
1.5
作者：
Julious, Steven A.;Mullee, Mark A.
通讯作者：
Mullee, Mark A.
影响因子：
--
作者：
Kim, Mimi
通讯作者：
Kim, Mimi