South African Cochrane Centre, Medical Research Council, Tygerberg, South Africa.
Health Info Libr J. 2011 Sep;28(3):210-5. doi: 10.1111/j.1471-1842.2011.00936.x. Epub 2011 Mar 30.
Research on identifying trials using geographic filters is limited.
To test the sensitivity and precision of a filter to identify African randomised controlled trials (RCTs).
We searched medline and embase for RCTs published in 2004 using a Cochrane filter for RCTs. The search was limited to HIV/AIDS but irrespective of location. Two investigators independently identified African RCTs from the retrieved records forming a reference set. We then repeated the search using an African geographic filter comprising country and regional terms forming the filter set. We compared the sensitivity and precision of the sets.
The medline reference set comprised 1799 records with 23 African RCTs; for embase, the reference set comprised 763 records with 37 African RCTs. The medline filter set comprised 180 records with 17 African RCTs; the embase filter set comprised 98 records with 27 African RCTs. Sensitivity of the filter was 74% (medline) and 73% (embase). Addition of the filter improved precision from 1.3% to 9.4% (medline) and from 5% to 28% (embase).
The African filter improved precision with some loss in sensitivity. Incomplete reporting of trial location in electronic bibliographic records restricts efficiency of geographic filters. Prospective trial registration should alleviate this.
针对使用地理筛选器识别试验的研究有限。
测试一种筛选器识别非洲随机对照试验（RCT）的灵敏度和精度。
我们使用 Cochrane RCT 筛选器在 2004 年发表的 medline 和 embase 中搜索 RCT。该搜索仅限于 HIV/AIDS，但不考虑地点。两名研究人员独立从检索到的记录中识别出非洲 RCT，形成参考集。然后，我们使用包含国家和地区术语的非洲地理筛选器重复搜索，形成筛选器集。我们比较了两个集合的灵敏度和精度。
medline 参考集包含 1799 条记录和 23 项非洲 RCT；embase 参考集包含 763 条记录和 37 项非洲 RCT。medline 筛选器集包含 180 条记录和 17 项非洲 RCT；embase 筛选器集包含 98 条记录和 27 项非洲 RCT。筛选器的灵敏度为 74%（medline）和 73%（embase）。添加筛选器后，精度从 1.3%提高到 9.4%（medline）和从 5%提高到 28%（embase）。
非洲筛选器提高了精度，但牺牲了部分灵敏度。电子书目记录中试验地点报告不完整，限制了地理筛选器的效率。前瞻性试验注册应能缓解这一问题。
