Savoie Isabelle, Helmer Diane, Green Carolyn J, Kazanjian Arminée
British Columbia Office of Health Technology Assessment, Centre for Health Services and Policy Research, University of British Columbia, Vancouver, Canada.
Int J Technol Assess Health Care. 2003 Winter;19(1):168-78. doi: 10.1017/s0266462303000163.
To evaluate the sensitivity and precision of various extended search methods in identifying randomized controlled trials (RCTs) for systematic reviews.
Prospective analysis of extended search methods (specialized databases or trial registries, reference lists, hand-searching, personal communication, and Internet) used in two systematic reviews of RCTs. The gold standard was the total number of RCTs identified by major databases (MEDLINE, EMBASE, etc.) and extended search strategies combined. Sensitivity was the proportion of all known RCTs identified by any extended search method. Precision reflected the proportion of all items uncovered by any extended search method that actually were RCTs.
The extended search identified 94 additional RCTs for the systematic reviews beyond those identified with the major databases. Specialized databases and trial registries had the highest sensitivity and precision for the lipid-lowering project (13.6% and 52.7%, respectively; p < .05) followed by scanning of reference lists (7.2% sensitivity and 41.9% precision; p <.05). Hand-searching was more effective than personal communication and Internet searching (1.7% sensitivity and 12.2% precision; p < .05). The acupuncture project had slightly different results, with the specialized databases and trial registries tied with the review of reference lists for highest sensitivity (14.2%). The precision followed the same trend as the lipid-lowering project (17.6% specialized databases; 8.3% reference lists; p < .05). A post-hoc analysis showed that 75 of the 94 RCTs were indexed in the major databases but missed by the major database search.
Extended searching identified additional RCTs for the systematic reviews beyond those found in major databases. Specialized databases and trial registries were most effective. An important number of RCTs were missed by the major database search. Timing and accuracy of indexing may explain this finding. The definitive measure, whether there is an association between the method used to uncover RCTs, the quality of the items uncovered and their impact on systematic review results, is yet to be determined.
评估各种扩展检索方法在识别用于系统评价的随机对照试验（RCT）中的敏感性和精确性。
对两项RCT系统评价中使用的扩展检索方法（专业数据库或试验注册库、参考文献列表、手工检索、个人交流和互联网）进行前瞻性分析。金标准是主要数据库（MEDLINE、EMBASE等）和扩展检索策略联合识别出的RCT总数。敏感性是通过任何扩展检索方法识别出的所有已知RCT的比例。精确性反映了通过任何扩展检索方法发现的所有条目中实际为RCT的比例。
扩展检索为系统评价识别出了94项主要数据库未识别出的额外RCT。专业数据库和试验注册库在降脂项目中具有最高的敏感性和精确性（分别为13.6%和52.7%；p <.05），其次是参考文献列表检索（敏感性7.2%，精确性41.9%；p <.05）。手工检索比个人交流和互联网检索更有效（敏感性1.7%，精确性12.2%；p <.05）。针灸项目的结果略有不同，专业数据库和试验注册库与参考文献列表检索的敏感性最高（均为14.2%）。精确性与降脂项目趋势相同（专业数据库为17.6%；参考文献列表为 8.3%；p <.05）。事后分析显示，94项RCT中有75项在主要数据库中被索引但被主要数据库检索遗漏。
扩展检索为系统评价识别出了主要数据库之外的额外RCT。专业数据库和试验注册库最为有效。主要数据库检索遗漏了大量RCT。索引的时间和准确性可能解释这一发现。用于发现RCT的方法、所发现条目的质量及其对系统评价结果的影响之间是否存在关联，这一决定性指标尚待确定。
