Distribution of Country of Origin in Studies Used in Cochrane Reviews

Citation: Wolff RF, Reinders S, Barth M, Antes G ( Distribution of Country of Origin in Studies Used in Cochrane Reviews Robert F. Wolff 0 Stefan Reinders 0 Michael Barth 0 Gerd Antes 0 Beverley J. Shea, Central Institute of Educational Technology, Canada 0 1 Institute of Medical Biometry and Medical Informatics, German Cochrane Centre, Department of Medical Biometry and Statistics, University Hospital Freiburg , Freiburg, Germany , 2 Faculty of Health Sciences, Bielefeld School of Public Health , Bielefeld, Germany , 3 Institut fu r Medizinische Informationsverarbeitung, Biometrie und Epidemiologie, Ludwig Maximilian University of Munich , Munich , Germany Background and Objective: Inclusion in systematic reviews is one important component in judging the potential impact of clinical studies upon practice and hence the 'value for money' of spending for clinical research. This study aims to quantify the distribution of countries of origin of clinical studies used in Cochrane Reviews (CRs), and to link these data to the size of a country and to its spending on research. Methods: Random sample of publications used for CRs published in Issue 1 2008 and of publications used in CRs in the field of complementary and alternative medicine (CAM). Publications without original data were excluded. Likely countries of origin determined based on abstracts/full texts. CIA World Factbook (population data) and OECD database (economic data) were used. Results: 1,000 random entries out of 140,005 references available in all specialities. In 876 (91.4%) of 959 eligible studies, country of origin was determined. The USA was the leading contributor (36.0% of the studies), followed by UK (13.4%), Canada (5.3%), Australia and Sweden (3.7%). In the CAM sample, country of origin was determined in 458 (93.5%) of 497 assessed studies. Again, the USA was the leading contributor (24.9%), with China also emerging as a significant contributor (24.7%) in this field. For both samples, the contribution of smaller countries (especially Scandinavian countries, Greece, and Ireland) became more noteworthy when considered in relation to population size and research spending. Conclusions: Our results support the leading roles of both the USA and the UK in publishing clinical papers. The emerging role of China can be seen, particularly related to CAM studies. Taking into account size of population and economic power, countries like France, Germany, Italy, and Spain provide small contributions. In contrast, smaller countries like Australia, Denmark, Finland, Ireland, New Zealand, and Sweden also play major roles. - Competing Interests: Dr. Antes is a member of the scientific board of the ISRCTN register. This did not alter the authors adherence to all PLoS ONE policies on sharing data and materials. Introduction Back in 1747, the Scottish naval surgeon James Lind conducted one of the first controlled clinical trials (CCT) [1]. Since the end of the Second World War hundreds of thousands of CCTs and randomised controlled trials (RCTs) have been conducted all over the world [2,3]. Today, clinical trials can be seen as the backbone of systematic reviews [4]. Systematic reviews have a decisive role in clinical decision making [5,6]. Studies assessing the geographical distribution of clinical research activity have confirmed the leading role of the USA in publishing scientific papers in various fields: in the top 50 biomedical journals [7], clinical cardiology [8], clinical radiology [9], clinical oncology [10], drug trials [11] and biomedical research [12]. In addition, various publications on the contribution of countries to publications of specific journals are available [13,14]. To date, we are aware of only one study that has examined the production of RCTs and CCTs per country across all specialities and journals [15]. The authors of this study used Clinical Trials, formerly known as Cochrane Central Register on Controlled Trials (CENTRAL), in the Cochrane Library to create a ranking of countries with respect to the numbers of published RCTs and CCTs [16]. In addition, they tried to assess the relationship between the number of inhabitants per country and publication rates by the performance of an ecological study. Based on this concept of Gluud and Nikolova [15], we have evaluated the studies used for systematic reviews published by the Cochrane Collaboration. The Cochrane Database of Systematic Reviews (Cochrane Reviews) as part of the Cochrane Library contains 3,372 reviews and 1,776 protocols for reviews (Issue 1 2008). As thorough searches are conducted for Cochrane Reviews (including handseaching and searches for non-English studies), they are likely to include a high proportion of the available studies in any clinical field [3]. Usage of a clinical study in systematic reviews can be used as a proxy for quality and the practical value of the trial. Systematic reviews and hence the studies included in them form the evidence body supporting any clinical guidance, such as guidelines, evidence-based patient information and websites, and reimbursement decisions (health technology assessments). Our study aims to determine the contribution of clinical studies per country across all specialties and to examine the production of clinical studies in the field of complementary and alternative medicine (CAM). We have also assessed the relationships between the contribution rate and the population size and spending on research and development of each country. Literature search The database of studies used for Cochrane Reviews published in Issue 1 2008 of the Cochrane Database of Systematic Reviews was used as a source of data. This database includes all studies retrieved for Cochrane Reviews, those which were finally included in reviews, those which were excluded as well as cited publications. The sample of CAM related studies was created from a selection of Cochrane Reviews, identified as CAM related reviews by the complementary and alternative medicine field of the Cochrane Collaboration [17]. All stages of study selection and data extraction were done by one of three reviewers (RW, SR or MB) and checked independently by a second reviewer (RW, SR or MB). Any disagreement during the selection, extraction, and assessment process was resolved by discussion and consensus. Study selection Samples of studies were drawn using the SURVEYSELECT command in SAS 9.1.3 Service Pack 4 and SPSS for Windows 11.5.1. Study samples were screened for fulfilling the inclusion criteria. Eligible studies were included in the process of assessing the country of origin. Inclusion criteria Publications assessed for inclusion in Cochrane Reviews were included. In a first step, we excluded studies awaiting assessment or marked as ongoing trials. Secondly, we excluded reviews, studies focussing on economical or methodological aspects, publications without original data (like editorials, comments, letters to the editor), stud (...truncated)