A comparison of handsearching versus EMBASE searching of the Annals of Saudi Medicine to identify reports of randomized controlled trials

Abstract

t is increasingly recognized that health care decision-making around the world needs to be informed by high quality and timely research evidence. The randomized controlled trial (RCT) has long been considered the “gold standard” in the hierarchy of evidence; randomized trials, involving sufficient numbers of participants, are essential to distinguish reliably between the effects of health care interventions and the effects of bias or chance. The synthesis of the results of these trials in systematic reviews can provide reliable evidence about the effects of these interventions. The Cochrane Collaboration is an international organization dedicated to improving health care for the world’s population by preparing, maintaining, and promoting the accessibility of Cochrane systematic reviews of the evidence of the effects of health care interventions. The validity of the results of a systematic review is highly dependent on the data included and a prerequisite is to include as unbiased and complete a set of relevant studies as possible. The Cochrane Collaboration has focused on the systematic electronic searching of MEDLINE and EMBASE and the systematic handsearching of currently over 2000 general and specialized health care journals for reports of RCTs. This handsearching involves reading each document in a journal to decide, according to the set Cochrane eligibility criteria, if it might be a report of a randomized trial. The efforts of the many volunteers working within The Cochrane Collaboration have added a substantial number of previously “buried” reports of RCTs to The Cochrane Central Register of Controlled Trials (CENTRAL) published in The Cochrane Library. Some of these reports of trials may have been “buried” as a result of inconsistencies in indexing (indexing bias), a lack of cover-to-cover indexing, or because they have been published in journals not indexed in the major health care databases such as MEDLINE and EMBASE (database bias) or in journals published in languages other than English (language bias). 6 There is a heightened interest among the scientific community in charting the publication of medical research by geographical region. Although no Iranian health care journals were indexed in MEDLINE at the time, a study of the number of MEDLINE-indexed publications originating from Iranian researchers from 1991 to 2002 identified 2060 articles. The number of these articles increased from 44 in 1991 to 508 in 2002. Four Iranian biomedical publications, namely Archives of Iranian Medicine, Iranian Journal of Medical Sciences, Iranian Biomedical Journal, and Daru were indexed in Excerpta Medica Database (EMBASE) in January 2002. An analysis conducted one year after indexing showed that these journals contributed almost 1/6 of the Iranian biomedical research output. The number of indexed journals in Iran has steadily increased in recent years and as of April 2006, 15 journals are indexed in EMBASE and one in MEDLINE. The Bahrain Branch of the UK Cochrane Center (UKCC) together with colleagues in Iran is actively seeking to minimize the effects of bias by addressing problems of study identification through a comprehensive handsearching program, Report