Impact of single centre status on estimates of intervention effects in trials with continuous outcomes: meta-epidemiological study.
Impact of single centre status on estimates of intervention effects in trials with continuous outcomes: meta-epidemiological study.
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DOI：
10.1136/bmj.e813
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发表时间：
2012-02-14
期刊：
影响因子：
--
通讯作者：
Ravaud P
中科院分区：
文献类型：
--
作者：
Bafeta A;Dechartres A;Trinquart L;Yavchitz A;Boutron I;Ravaud P
目的比较单中心和多中心连续结局随机对照试验的干预效果估计。设计荟萃流行病学研究。数据来源：2007年1月至2010年1月，Cochrane系统评价数据库中发表了26项荟萃分析，共292项随机对照试验（177项单中心试验，115项多中心试验）的连续结果。数据提取使用Cochrane Collaboration的偏倚风险工具提取试验特征、单中心或多中心状态、偏倚风险和结果。采用标准化平均差异估计干预效果。对于每个荟萃分析，随机效应荟萃回归用于估计单中心和多中心试验之间的标准化平均差异。标准化平均差异的差异通过随机效应荟萃分析模型汇集在meta分析中。标准化平均差异小于0的综合差异表明，平均而言，单中心试验比多中心试验显示出更大的治疗效果。由于单中心试验可能比多中心试验更容易出现发表偏倚，而且可能比多中心试验的方法学质量更低，因此敏感性分析是在调整样本量和偏倚风险域的情况下进行的。结果单中心试验的干预效果大于多中心试验（标准化平均差异的综合差异为- 0.09,95%可信区间为- 0.17至- 0.01，P=0.04），个体荟萃分析的异质性较低（I2=0%，荟萃分析方差τ2=0.00）。调整样本量稍微减弱了差异（- 0.08,- 0.17至0.01）。对偏倚风险的调整产生了类似的估计，置信区间更宽，其中一些超过0（总体偏倚风险为- 0.09,- 0.17至0.00）。平均而言，具有连续结果的单中心临床试验的干预效果略大于多中心试验。需要进一步的研究来调查这些差异的潜在原因。
Objective To compare estimates of intervention effects between single centre and multicentre randomised controlled trials with continuous outcomes. Design Meta-epidemiological study. Data sources 26 meta-analyses totalling 292 randomised controlled trials (177 single centre, 115 multicentre) with continuous outcomes published between January 2007 and January 2010 in the Cochrane database of systematic reviews. Data extraction Data were extracted on characteristics of trials, single or multicentre status, risk of bias using the risk of bias tool of the Cochrane Collaboration, and results. Data synthesis The intervention effects were estimated with standardised mean differences. For each meta-analysis, random effects meta-regression was used to estimate the difference in standardised mean differences between single centre and multicentre trials. Differences in standardised mean differences were then pooled across meta-analyses by a random-effects meta-analysis model. A combined difference in standardised mean differences of less than 0 indicated that single centre trials showed larger treatment effects, on average, than did multicentre trials. Because single centre trials may be more prone to publication bias and may have lower methodological quality than multicentre trials, sensitivity analyses were done with adjustment for sample size and domains of the risk of bias tool. Results Single centre trials showed larger intervention effects than did multicentre trials (combined difference in standardised mean differences −0.09, 95% confidence interval −0.17 to −0.01, P=0.04), with low heterogeneity across individual meta-analyses (I2=0%, between meta-analyses variance τ2=0.00). Adjustment for sample size slightly attenuated the difference (−0.08, −0.17 to 0.01). Adjustment for risk of bias yielded similar estimates with wider confidence intervals, some of them crossing 0 (−0.09, −0.17 to 0.00 for overall risk of bias). Conclusions On average, single centre clinical trials with continuous outcomes showed slightly larger intervention effects than did multicentre trials. Further research is needed to investigate potential causes of these differences.
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影响因子：
168.9
作者：
Moher, D;Pham, B;Klassen, TP
通讯作者：
Klassen, TP
影响因子：
39.2
作者：
Dechartres, Agnes;Boutron, Isabelle;Ravaud, Philippe
通讯作者：
Ravaud, Philippe
影响因子：
120.7
作者：
Boutron, I;Tubach, F;Ravaud, P
通讯作者：
Ravaud, P
DOI：
10.1111/j.1749-6632.1993.tb26343.x
发表时间：
1993-01-01
期刊：
DOING MORE GOOD THAN HARM: THE EVALUATION OF HEALTH CARE INTERVENTIONS
影响因子：
--
作者：
DICKERSIN, K;MIN, YI
通讯作者：
MIN, YI
影响因子：
7.2
作者：
Furukawa, TA;Barbui, C;Watanabe, N
通讯作者：
Watanabe, N