Schwenk Wolfgang, Haase Oliver, Günther Nina, Neudecker Jens
Universitätsklinik für Allgemein Visceral-, Gefäss- und Thoraxchirurgie, Charité-Universitätsmedizin Berlin, Campus Mitte, Charitéplatz 1, 10117, Berlin, Germany.
Int J Colorectal Dis. 2007 Nov;22(11):1369-76. doi: 10.1007/s00384-007-0318-7. Epub 2007 May 26.
Randomised, controlled trials (RCT) and systematic reviews of RCT with meta-analysis are considered to be of highest methodological quality and therefore are given the highest level of evidence (Ia/b). Although, "low-quality" RCT may be downgraded to level of evidence IIb, the methodological quality of each individual RCT is not respected in detail in this classification of the level of evidence.
Within a systematic Cochrane Review of RCT on short-term benefits of laparoscopic or conventional colorectal resections, the methodological quality of all included RCT was evaluated. All RCT were assessed by the Evans and Pollock questionnaire (E and P increasing quality from 0-100) and the Jadad score (increasing quality from 0-5).
Publications from 28 RCT printed from 1996 to 2005 were included in the analysis. Methodological quality of RCT was only moderate [E & P 55 (32-84); Jadad 2 (1-5)]. There was a significant correlation between the E & P and the Jadad score (r = 0.788; p < 0.001). Methodological quality of RCT slightly increased with increasing number of patients included (r = 0.494; p = 0.009) and year of publication (r = 0.427; p = 0.03). Meta-analysis of all RCT yielded clinically relevant differences for overall and local morbidity when compared to meta-analysis of "high-quality" (E & P > 70) RCT only.
The methodological quality of reports of RCT comparing laparoscopic and open colorectal resection varies considerably. In a systematic review, methodological quality of RCT should be assessed because meta-analysis of "high-quality" RCT may yield different results than meta-analysis of all RCT.
随机对照试验（RCT）以及采用荟萃分析的RCT系统评价被认为具有最高的方法学质量，因此被赋予最高级别的证据（Ia/b）。尽管“低质量”的RCT可能会被降级为证据级别IIb，但在这种证据级别的分类中，并未详细考虑每个RCT的方法学质量。
在一项关于腹腔镜或传统结直肠切除术短期获益的Cochrane系统评价中，对所有纳入的RCT的方法学质量进行了评估。所有RCT均通过埃文斯和波洛克问卷（E和P，质量从0至100递增）以及雅达评分（质量从0至5递增）进行评估。
分析纳入了1996年至2005年发表的28项RCT的文献。RCT的方法学质量仅为中等[E&P 55（32 - 84）；雅达2（1 - 5）]。E&P与雅达评分之间存在显著相关性（r = 0.788；p < 0.001）。RCT的方法学质量随着纳入患者数量的增加（r = 0.494；p = 0.009）以及发表年份的增加（r = 0.427；p = 0.03）而略有提高。与仅对“高质量”（E&P > 70）RCT进行荟萃分析相比，对所有RCT进行荟萃分析得出了总体和局部发病率方面具有临床意义的差异。
比较腹腔镜和开放结直肠切除术的RCT报告的方法学质量差异很大。在系统评价中，应评估RCT的方法学质量，因为对“高质量”RCT进行荟萃分析可能会得出与对所有RCT进行荟萃分析不同的结果。
