A bibliometric analysis of the global research in ankylosing spondyloarthritis (2008–2017)

The current study was to investigate the quantity and quality of researches in the field of ankylosing spondylitis, and to reveal the characteristics of worldwide productivity on this disease. This was a bibliometric study on ankylosing spondylitis using Web of Science. The numbers of papers, citations, research output normalized by population and gross domestic product, and the main active countries were analyzed. A total number of 7239 papers were published between 2008 and 2017. The yearly number of papers published during this period showed a significant increase (p < 0.001). North America, West Europe and East Asia were the main regions for AS papers. High-income countries contributed the greatest proportion of papers (70.49%). The research productivity from middle- and low-income countries was low (29.45%; 0.06%). The United States was the country with the greatest contributions between 2008 and 2017 (12.47%), followed by China (12.17%), Turkey (8.34%), Germany (7.82%), and the United Kingdom (5.97%). Significantly positive correlations were proved between the number of papers and population/gross domestic product (p < 0.05). From 2013, the number of AS publications by the authors from China exceeded those from the United States. However, China had far less total citations (7219 vs. 22,043) and average citations (8.19 vs. 24.41) than the United States. Denmark had the greatest productivity when normalized by population, followed by Norway, and Netherlands. When normalized by gross domestic product, Denmark led the top list, followed by Netherlands, and Greece. Papers from Australia showed the highest average citation (32.64), followed by Netherlands (31.63), and Germany (26.88). The current study showed a noticeable growth in global research output on ankylosing spondylitis between 2008 and 2017. High-income countries especially the United States had the greatest contributions. The contributions from middle- and low-income countries were considerably small. The number of papers published by countries was positively associated with their population and gross domestic product. Although China had exceeded the United States in the quantity of yearly AS publications, the quality of papers from China was lower compared to the United States. European countries may have better performance relative to their population and economic size.