Royle P L, Bain L, Waugh N R
Department of Public Health, University of Aberdeen, Aberdeen, UK.
Diabet Med. 2005 Oct;22(10):1386-93. doi: 10.1111/j.1464-5491.2005.01645.x.
To analyse the effect on systematic reviews in diabetes interventions of including only trials that are indexed in medline, and to assess the impact of adding trials from other databases and the grey literature.
All systematic reviews of diabetes interventions which included a meta-analysis of randomized controlled trials, and were published since 1996, were selected. The impact on the meta-analysis of including only those trials indexed in medline, and the effect of then adding trials from other sources, was assessed. Where possible this was measured quantitatively, by redoing the meta-analysis, otherwise a qualitative estimate was made.
Forty-four systematic reviews met our inclusion criteria. There were 120 articles reporting trial data which were not indexed in medline. These came from 52% of the reviews. In 34% of the reviews, basing a meta-analysis on a search of only medline would miss trials that could affect the result. Sources of non-medline data which had the biggest effect on the meta-analyses were journal articles from central and embase (mainly in Diabetes, Nutrition and Metabolism) and unpublished data (mainly from industry). The exceptions were journal articles on herbal medicine, mostly indexed in Chinese language databases.
A search of only the medline database is insufficient for systematic reviews of diabetes, because in about 34% of reviews the missed trials could affect the results of the meta-analysis. It is recommended that central (on the Cochrane Library) also be searched. Scanning meeting abstracts, and seeking unpublished data are also recommended if the intervention has only recently been introduced.
分析仅纳入在Medline中索引的试验对糖尿病干预系统评价的影响，并评估添加来自其他数据库和灰色文献的试验的影响。
选择自1996年以来发表的所有包含随机对照试验荟萃分析的糖尿病干预系统评价。评估仅纳入Medline中索引的那些试验对荟萃分析的影响，以及随后添加来自其他来源试验的效果。在可能的情况下，通过重新进行荟萃分析进行定量测量，否则进行定性估计。
44项系统评价符合我们的纳入标准。有120篇报告试验数据的文章未在Medline中索引。这些文章来自52%的评价。在34%的评价中，仅基于Medline检索进行荟萃分析会遗漏可能影响结果的试验。对荟萃分析影响最大的非Medline数据来源是来自CENTRAL和Embase的期刊文章（主要涉及糖尿病、营养与代谢领域）以及未发表的数据（主要来自行业）。关于草药的期刊文章是例外，大多在中国语言数据库中索引。
仅检索Medline数据库对于糖尿病系统评价是不够的,因为在约34%的评价中，遗漏的试验可能影响荟萃分析结果。建议也检索CENTRAL（Cochrane图书馆中的）。如果干预措施是最近才引入的，还建议浏览会议摘要并寻找未发表的数据。
