Disparities in cardiovascular research output and citations from 52 african countries: A time-trend, bibliometric analysis (1999-2008)

Background--Cardiovascular research output and citations of publications from Africa have historically been low yet may be increasing. However, data from the continent are limited. Methods and Results--To evaluate the cardiovascular research output and citations from 52 African countries between 1999 and 2008, we created a bibliometric filter to capture cardiovascular research articles published in the Web of Knowledge based on specialist journals and title words. Two coauthors with expertise in cardiovascular medicine tested and refined this filter to achieve >90% precision and recall. We matched retrieved records with their associated citation reports and calculated the running 5-year citation count postpublication, including the year of publication. Publications from Africa were identified by author addresses. South Africa published 872 cardiovascular research papers, Egypt 393, Tunisia 264, and Nigeria 192 between 1999 and 2008. The number of publications increased over the time period for a small number of countries (range 0.1 to 4.8 more publications per year by fractional count). Most countries' citations were low (<50), but citations were greatest for South Africa (7063), Egypt (2557), Tunisia (903), and Nigeria (540). The same countries had the greatest annual increase in 5-year citation index values: 65 (95% CI: 30, 99) for South Africa, 46 (34, 58) for Egypt, 22 (15, 28) for Tunisia, and 8 (2, 14) for Nigeria. The burden of cardiovascular disease had a weak and inconsistent relationship to cardiovascular publications (r²=0.07, P=0.05). Greater gross domestic product was associated with more cardiovascular publications in 2008 (r²=0.53, P<0.0001). Conclusions--The increases in cardiovascular research outputs from Africa are concentrated in a few countries. The reasons for regional differences in research outputs require further investigation, particularly relative to competing disease burdens. Higher prioritization of cardiovascular research funding from African countries is warranted.