Meta-analyses Cochrane Collaboration

Cochrane Library. The Cochrane Library [44] includes The Cochrane Database of Systematic Reviews, a collection of regularly updated, systematic reviews of the effects of health care. It is maintained by contributors to the Cochrane Collaboration. Cochrane reviews are reviews mainly of randomized controlled trials. To minimize bias, evidence is included or excluded on the basis of explicit quality criteria. Data are often combined statistically, with meta-analysis, to increase the power of the findings of numerous studies, each too small to produce reliable results individually. Database of Abstracts of Reviews of Effectiveness is also included. It consists of critical assessments and structured abstracts of good systematic reviews published elsewhere. The Cochrane Controlled Trials Register with bibliographic information on controlled trials and other sources of information on the science of reviewing research and evidence-based health care are part of the Cochrane Library. It is commercially available on CD-ROM or the Internet. 

Leontiadis GI, Sharma VK, Howden CW. Systematic review and meta-analysis proton pump inhibitor treatment for ulcer bleeding reduces transfusion requirements and hospital stay-results from the Cochrane Collaboration. Aliment Pharmacol Ther 2005 22 169-74. 

Sarcoma Meta-analysis Collaboration. Adjuvant chemotherapy for localised resectable soft tissue sarcoma in adults. Cochrane Database Syst Rev 1999. Issue 4. 

In a Cochrane Collaboration meta-analysis of trials of zonisamide, levetiracetam, oxcarbazepine, and rema-cemide, there were no significant differences in efficacy among the four drugs (4). The relative risks for treatment withdrawal were also not significantly different. 

Since then the importance of meta-analysis has grown. Not only has there been an explosion in published analyses over the past twenty years, but initiatives such as that of the Cochrane collaboration of databases as well as the trend towards evidence-based medicine make it both easier to use meta-analysis on the one hand and less acceptable not to do so on the other. In drug development, while being satisfied with an expert s judgement alone in the past, the regulator now expects to see it backed up with a formal overview of all studies. (See, for example, ICH E9 (International Conference on Harmonisation, 1999).) Like them or hate them, meta-analyses are here to stay. 

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