Trends in Worldwide Research in Hypertension Over the Period 1999-2018: A Bibliometric Study

Abstract

Bibliometric analysis, a powerful tool for assessing trends in research output, was employed to analyze the evolution of hypertension research over a 20-year period. The analysis was based on 90 308 original articles and a citation analysis. The use of bibliometric as a potential tool for shaping research policy at the institution or country level was also explored. The number of published hypertension articles increased by 43.5% over the 20-year period. By contrast, the increase in the number of articles in all medical disciplines was 96%, and in the cardiovascular field was 64%. Of the 6 countries producing the largest number of articles, the United States was consistently the major contributor. There was a slight decrease from Japan, a slight increase from the United Kingdom, and relatively stable output from Germany and Italy over the study period. Output from China showed the strongest growth. The trends in Specialization Index and Category Normalized Citation Impact varied by country. In Russia, Poland, and Brazil, increases in output were greater for hypertension research than for medical research in general. The United Kingdom and Denmark had greater hypertension research output than the other countries. VOSviewer analysis showed an intensification of collaborations between countries and a shift, over 10 years, from 3 clusters towards 2 clusters. Such analysis may help to shape research policy at the country level and can be similarly performed for institutions. Historical changes in hypertension research can be monitored over decades if the same channels continue to be used for communication of scientific results.

Keywords: PubMed; bibliometrics; category normalized citation impact; publications; specialization index.

Figure 1.

Numbers of articles by year of publication for the 6 countries that had a total of >5000 articles related to hypertension over the 20-year study period.

Figure 2.

Changes in specialization indices and Category Normalized Citation Impacts for the periods 1999–2003 to 2014–2018 for the 20 countries making the most contribution to hypertension research output.

Figure 3.

VOSviewer analysis of collaborations for the periods 1999–2003 (Top) and 2014–2018 (bottom), based on the top 10% of articles cited. The size of each colored circle is proportional to the total number of articles with authors from that country. The distance between 2 countries is inversely proportional to the number of articles from those 2 countries.