s. A few more recent reviews have also studied the results of non-randomized, observational studies
. The results of these systematic review
s are published as "Cochrane Reviews" in the Cochrane Library
of Cochrane Collaboration illustrates a meta analysis of data from seven randomized controlled trials (RCTs), comparing one health care treatment with a placebo
in a forest plot
. The diagram shows the results of a systematic review
and meta analysis on inexpensive course of corticosteroid
given to women about to give birth
too early – the evidence on effectiveness that would have been revealed had the available RCTs been reviewed systematically a decade later. This treatment reduces the odds
of the babies of such women dying from the complications of immaturity by 30–50%. Because no systematic review of these trials had been published until 1989, most obstetricians had not realised that the treatment was so effective and therefore many premature babies have probably suffered or died unnecessarily.
HistoryThe Cochrane Collaboration was founded in 1993 under the leadership of Iain Chalmers
. It was developed in response to Archie Cochrane
's call for up-to-date, systematic reviews of all relevant randomized controlled trials of health care.
Cochrane's suggestion that the methods used to prepare and maintain reviews of controlled trials in pregnancy and childbirth should be applied more widely was taken up by the Research and Development Programme, initiated to support the United Kingdom's National Health Service
. Through the NHS R&D programme, led by the first Director of Research and Development Professor Michael Peckham
, funds were provided to establish a 'Cochrane Centre', to collaborate with others, in the UK and elsewhere, to facilitate systematic reviews of randomized controlled trials across all areas of health care..
In October 1995, The Collaboration formed the Cochrane Consumer Network to incorporate patient perspectives into the review process. Shortly thereafter, new 'plain language summaries' provided users with a jargon-free synopsis of each systematic review.
Goal and principlesThe goal of the collaboration is to help people make well informed decisions about health care by preparing, maintaining and ensuring the accessibility of systematic reviews of the effects of health care interventions.
The principles of the Cochrane Collaboration are:
- "building on the enthusiasm of individuals"
- avoiding duplication
- minimizing bias
- keeping up to date
- striving for relevance
- promoting access
- ensuring quality
- enabling wide participation
CriticismA 2011 study done to disclose possible conflicts of interests in underlying research studies used for medical meta-analyses reviewed 29 meta-analyses and found that conflicts of interests in the studies underlying the meta-analyses were rarely disclosed. The 29 meta-analyses included 11 from general medicine journals; 15 from specialty medicine journals, and 3 from the Cochrane Database of Systematic Reviews. The 29 meta-analyses reviewed an aggregate of 509 randomized controlled trials (RCTs). Of these, 318 RCTs reported funding sources with 219 (69%) industry funded. 132 of the 509 RCTs reported author conflict of interest [COI] disclosures, with 91 studies (69%) disclosing industry financial ties with one or more authors. The information was, however, seldom reflected in the meta-analyses. Only two (7%) reported RCT funding sources and none reported RCT author-industry ties. The authors concluded “without acknowledgement of COI due to industry funding or author industry financial ties from RCTs included in meta-analyses, readers’ understanding and appraisal of the evidence from the meta-analysis may be compromised.” Noting that most assessment tools for meta-analysis do not include a domain for study funding source the authors state: “Currently, The Cochrane Collaboration’s Risk of Bias tool includes an optional 'other sources of bias' domain, which meta-analysts could use to include information on COIs. We recommend that The Cochrane Collaboration consider formalizing the requirement to assess potential bias from COIs.”
- Evidence-based medicineEvidence-based medicineEvidence-based medicine or evidence-based practice aims to apply the best available evidence gained from the scientific method to clinical decision making. It seeks to assess the strength of evidence of the risks and benefits of treatments and diagnostic tests...
- Cochrane LibraryCochrane LibraryThe Cochrane Library is a collection of databases in medicine and other healthcare specialties provided by the Cochrane Collaboration and other organisations. At its core is the collection of Cochrane Reviews, a database of systematic reviews and meta-analyses which summarize and interpret the...
- Systematic reviewSystematic reviewA systematic review is a literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...
- Cochrane Consumer Network