Endometriosis and its global research architecture: an in-depth density-equalizing mapping analysis

Abstract

Background: Endometriosis is one of the most common gynecological diseases. It is still a chameleon in many aspects and urges intense research activities in the fields of diagnosis, therapy and prevention. Despite the need to foster research in this area, no in-depth analysis of the global architecture of endometriosis research exists yet.

Methods: We here used the NewQIS platform to conduct a density equalizing mapping study, using the Web of Science as database with endometriosis related entries between 1900 and 2009. Density equalizing maps of global endometriosis research encompassing country-specific publication activities, and semi-qualitative indices such as country specific citations, citation rates, h-Indices were created.

Results: In total, 11,056 entries related to endometriosis were found. The USA was leading the field with 3705 publications followed by the United Kingdom (952) and Japan (846). Concerning overall citations and country-specific h-Indices, the USA again was the leading nation with 74,592 citations and a modified h-Index of 103, followed by the UK with 15,175 citations (h-Index 57). Regarding the citation rate, Sweden and Belgium were at top positions with rates of 22.46 and 22.26, respectively. Concerning collaborative studies, there was a steep increase in numbers present; analysis of the chronological evolution indicated a strong increase in international collaborations in the past 10 years.

Conclusions: This study is the first analysis that illustrates the global endometriosis research architecture. It shows that endometriosis research is constantly gaining importance but also underlines the need for further efforts and investments to foster research and ultimately improve endometriosis management on a global scale.

Keywords: Density equalizing; Endometriosis; Mapping; Research architecture.

Fig. 1

a Density-equalizing map of total endometriosis publications in each country. The area of each country was scaled in proportion to its total number of publications. Different colors encode numbers of endometriosis publications. This DEMP figure was generated by the authors as described in the methods section. b Chronological evolution of endometriosis-related publications. The red dotted line indicates the steep increase in publication activity visible after 1990

Fig. 2

a Density-equalizing map of country total citations of endometriosis publications. The area of each country was scaled in proportion to its total number of citations. Colors encode numbers of citations. b Density-equalizing map of country citation rate of endometriosis publications. The area of each country was scaled in proportion to its citation rate. Colors encode numbers of citations. These DEMP figures were generated by the authors as described in the methods section

Fig. 3

a International collaborations from 1983 to 2009. b Number of co-authors

Fig. 4

a Number of collaborative items published in a joint effort between two countries dedicated to research in the field of endometriosis. The figure depicts only cooperations of countries with more than 20 collaborative publications b Proportions of international collaborative efforts among all publications of the ten most proliferative countries in endometriosis research

Fig. 5

a Distribution of subject area assignments per endometriosis publication. b Most frequently assigned subject areas

Fig. 6

The 15 most prolific journals in endometriosis research with number of articles, number of citations and citation rate