Sassi Franco, Archard Luke, McDaid David
Department of Social Policy and Administration - LSE Health and Social Care, London, United Kingdom.
Med Care. 2002 May;40(5):387-94. doi: 10.1097/00005650-200205000-00004.
As the health care economic-evaluation literature continues to grow, a need for sound methods to conduct systematic reviews of the existing evidence is emerging. So far, reviews of economic evaluations have relied upon noncomprehensive sources and have adopted simplistic search methods, both likely to lead to biased results.
To provide evidence of the performance of alternative approaches for identifying published health care economic evaluations and to illustrate what forms of bias may affect systematic reviews of such studies.
The sensitivity and specificity of alternative search strategies were tested for the period January to March 1997, using seven major medical and social science literature databases, one economic evaluation database and a published bibliography. Studies were selected blindly by pairs of reviewers (agreement 94.1%-96.5%), using a two-stage procedure.
By limiting the scope of a review to Medline and by using appropriate search strategies, researchers may significantly reduce the number of nonrelevant references retrieved by their electronic searches (sensitivity 72%, specificity 75%, compared with more extensive strategies), which require exclusion by manual screening. The yield of searches based on specialized bibliographies and databases may be different because of variations in selection criteria, coverage and time lag for inclusion of references.
Medline is the key source for reviews of economic evaluations. Researchers may select from the search strategies proposed in this paper the one that offers an optimal balance between sensitivity and specificity in relation to the aims of their review. Manual searches and searches of databases other than Medline have a limited incremental yield. The sensitivity of all search strategies increases when tighter methodological standards are set, but more research is needed on methods for identifying methodologically sound studies.
随着医疗保健经济评估文献不断增多，对现有证据进行系统评价的可靠方法的需求日益凸显。到目前为止，经济评估的综述依赖于不全面的来源，并采用了简单化的检索方法，这两者都可能导致有偏差的结果。
提供有关识别已发表的医疗保健经济评估的替代方法的性能证据，并说明可能影响此类研究系统评价的偏差形式。
1997年1月至3月期间，使用七个主要的医学和社会科学文献数据库、一个经济评估数据库和一份已发表的书目，对替代检索策略的敏感性和特异性进行了测试。研究由成对的评审员盲目选择（一致性为94.1%-96.5%），采用两阶段程序。
通过将综述范围限制在Medline，并使用适当的检索策略，研究人员可以显著减少电子检索中检索到的不相关参考文献数量（敏感性72%，特异性75%，与更广泛的策略相比），这些参考文献需要人工筛选排除。由于选择标准、覆盖范围和参考文献收录的时间滞后存在差异，基于专门书目和数据库的检索结果可能不同。
Medline是经济评估综述的关键来源。研究人员可以从本文提出的检索策略中选择一种，该策略在敏感性和特异性之间提供了与综述目的相关的最佳平衡。人工检索和Medline以外的数据库检索的增量收益有限。当设定更严格的方法标准时，所有检索策略的敏感性都会提高，但需要更多关于识别方法学上合理的研究的方法的研究。
