Tricco Andrea C, Tetzlaff Jennifer, Pham Ba', Brehaut Jamie, Moher David
Chalmers Research Group, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, Ontario, Canada.
J Clin Epidemiol. 2009 Apr;62(4):380-386.e1. doi: 10.1016/j.jclinepi.2008.08.008. Epub 2009 Jan 6.
To determine which factors predict favorable results and positive conclusions in systematic reviews (SRs) and to assess the level of agreement between SR results and conclusions.
A sample of 296 English SRs indexed in MEDLINE (November, 2004) was obtained. Two investigators independently categorized SR characteristics, results, and conclusions. Descriptive analyses and logistic regression predicting favorable results (nonstatistically significant and statistically significant positive) and positive conclusions were conducted. The level of concordance between results and conclusions was assessed using a weighted-kappa statistic.
Overall, 36.5% of the SRs had favorable results, increasing to 57.7% for Cochrane and 64.3% for non-Cochrane reviews with a meta-analysis of the primary outcome. Non-Cochrane reviews with a meta-analysis of the primary outcome were twice as likely to have positive conclusions as Cochrane reviews with such an analysis (P-value<0.05). The weighted kappa for agreement between SR results and conclusions was 0.55. It was lower for Cochrane (0.41) vs. non-Cochrane (0.67) reviews.
SRs including a meta-analysis of the primary outcome may be affected by indirect publication bias in our sample. Differences between the results and conclusions of Cochrane and non-Cochrane reviews were apparent. Further research on publication-related issues of SRs is warranted.
确定哪些因素可预测系统评价（SR）的良好结果和积极结论，并评估SR结果与结论之间的一致性水平。
获取了2004年11月MEDLINE索引的296篇英文SR样本。两名研究者独立对SR的特征、结果和结论进行分类。进行了描述性分析和逻辑回归，以预测良好结果（非统计学显著和统计学显著阳性）和积极结论。使用加权kappa统计量评估结果与结论之间的一致性水平。
总体而言，36.5%的SR有良好结果，对于Cochrane评价，这一比例增至57.7%，对于对主要结局进行荟萃分析的非Cochrane评价，该比例为64.3%。对主要结局进行荟萃分析的非Cochrane评价得出积极结论的可能性是进行此类分析的Cochrane评价的两倍（P值<0.05）。SR结果与结论之间一致性的加权kappa为0.55。Cochrane评价（0.41）的该值低于非Cochrane评价（0.67）。
在我们的样本中，包括对主要结局进行荟萃分析的SR可能受到间接发表偏倚的影响。Cochrane评价与非Cochrane评价的结果和结论之间存在明显差异。有必要对SR与发表相关的问题进行进一步研究。
