Indexing of clinical trials in LILACS: Assessment of 721 articles published in cardiology journals

Abstract Systematic reviews are considered the highest level of evidence for decision making in health care issues. One of the first steps of a SR involves identifying all relevant clinical trials on the topic of interest. However, the retrieval of clinical trials in a database partially depends on the article indexing quality. The aim of this article is to evaluate the adequacy of indexing of clinical trials as a publication type in the LILACS database in a sample of articles published in cardiology journals. This cross-sectional study analyzed the indexing quality of clinical trials published between 2008 and 2009 in cardiology journals indexed in LILACS. Two independent reviewers identified and reclassified all original studies published in these journals as being clinical trials or other types of studies. The result of their classification was compared with the indexing publication type produced by LILACS. A total of 721 articles published in 11 cardiology journals were included. The reviewers classified 63 articles as clinical trials; 44 of these were correctly indexed in LILACS, while 19 were indexed as other types of studies (false negatives). The reviewers classified 658 articles as non-clinical trials; 651 were correctly indexed and 7 were incorrectly indexed in LILACS as being clinical trials (false positives). The sensitivity, specificity and global accuracy of LILACS indexing were 69.8%, 98.9% and 96.4% (695/721), respectively. Almost one third of the clinical trials published in LILACS-indexed Cardiology journals are not adequately indexed. The indexing quality of the studies published in these journals must be improved.摘要：系统性综述（Systematic review, SR）被视作卫生保健领域决策的最高等级证据。系统性综述的首要步骤之一，即为识别与研究主题相关的全部临床试验。然而，数据库中临床试验的检索效果，在一定程度上取决于文章的标引质量。本文旨在以心血管病学期刊发表的文章为样本，评估LILACS数据库中将临床试验作为出版物类型的标引充分性。本横断面研究分析了2008至2009年间，收录于LILACS的心血管病学期刊中发表的临床试验的标引质量。两名独立审稿人将上述期刊发表的所有原创研究，重新归类为临床试验或其他类型研究，并将二人的分类结果与LILACS生成的出版物类型标引信息进行比对。本研究共纳入11种心血管病学期刊发表的721篇文章。其中，两名审稿人将63篇归类为临床试验：44篇在LILACS中得到正确标引，19篇被标引为其他研究类型（假阴性，false negatives）；将658篇归类为非临床试验，其中651篇得到正确标引，7篇被错误标引为临床试验（假阳性，false positives）。LILACS标引的灵敏度、特异度及整体准确率分别为69.8%、98.9%和96.4%（695/721）。在收录于LILACS的心血管病学期刊中，近三分之一的临床试验未得到充分标引，此类期刊发表的研究的标引质量亟待提升。