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. 2011 Apr 19;6(4):e18798.
doi: 10.1371/journal.pone.0018798.

Distribution of country of origin in studies used in Cochrane Reviews

Robert F Wolff  1 , Stefan Reinders, Michael Barth, Gerd Antes
Affiliations

Distribution of country of origin in studies used in Cochrane Reviews

Robert F Wolff et al. PLoS One. .

Abstract

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.

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Conflict of interest statement

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.

Figures

Figure 1
Figure 1. Flow diagram according to the QUOROM-statement with the total number of studies used for Cochrane Reviews and the number included in the present study.
CAM = Complementary and alternative medicine.
See this image and copyright information in PMC

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