A Blümle1, G Antes. 1. Deutsches Cochrane Zentrum, Institut für Medizinische Biometrie und Medizinische Informatik, Universitätsklinikum Freiburg, Stefan-Meier-Strasse 26,79104 Freiburg. bluemle@cochrane.de
Abstract
BACKGROUND AND OBJECTIVE: The identification of all available and relevant study reports is mandatory for a comprehensive inclusion of all eligible randomised controlled trials (RCTs) and controlled clinical trials (CCTs) in systematic reviews. Incorrect indexing and incomplete compilation of health care journals in electronic databases impair the result of a systematic literature search. An additional search in medical journals which are not listed in electronic databases is necessary to obtain greater search completeness. METHODS: Within the scope of the Handsearching project of the Cochrane Collaboration, 85 health care journals were searched for RCTs and CCTs. The identified trial reports were compared with all relevant trials included in Medline. The identified study reports had been published in the Cochrane Library and were thus available worldwide for inclusion in systematic reviews. RESULTS: 2614 volumes of 85 journals (3789 journal volumes) were searched for RCTs and CCTs. 18 491 controlled trials (10 218 RCTs und 8 273 CCTs) were identified, 10 165 (55 %) of which were not included in Medline. None of the identified trials published in 27 (32%) journals had been included in Medline. CONCLUSIONS: There is a gap between the number of handsearch results and the number of Medline-indexed RCTs and CCTs for almost every searched health care journal. Although many journals have already been searched and many clinical trials could be identified, the hand-searching project will be continued prospectively and retrospectively to ensure the completeness of the literature compilation. Journals and volumes that are not indexed in Medline should always be searched for and the identified reports should be published in the Cochrane Library.
BACKGROUND AND OBJECTIVE: The identification of all available and relevant study reports is mandatory for a comprehensive inclusion of all eligible randomised controlled trials (RCTs) and controlled clinical trials (CCTs) in systematic reviews. Incorrect indexing and incomplete compilation of health care journals in electronic databases impair the result of a systematic literature search. An additional search in medical journals which are not listed in electronic databases is necessary to obtain greater search completeness. METHODS: Within the scope of the Handsearching project of the Cochrane Collaboration, 85 health care journals were searched for RCTs and CCTs. The identified trial reports were compared with all relevant trials included in Medline. The identified study reports had been published in the Cochrane Library and were thus available worldwide for inclusion in systematic reviews. RESULTS: 2614 volumes of 85 journals (3789 journal volumes) were searched for RCTs and CCTs. 18 491 controlled trials (10 218 RCTs und 8 273 CCTs) were identified, 10 165 (55 %) of which were not included in Medline. None of the identified trials published in 27 (32%) journals had been included in Medline. CONCLUSIONS: There is a gap between the number of handsearch results and the number of Medline-indexed RCTs and CCTs for almost every searched health care journal. Although many journals have already been searched and many clinical trials could be identified, the hand-searching project will be continued prospectively and retrospectively to ensure the completeness of the literature compilation. Journals and volumes that are not indexed in Medline should always be searched for and the identified reports should be published in the Cochrane Library.