Hematology research output from Chinese authors and other countries: a 10-year survey of the literature

As shown in Figure 1, only China and South Korea exhibited a sustained trend in growth between 2004 and 2013 with respect to the number of publications in hematology-related journals. The USA had an upward trend in the number of hematology articles published between 2004 and 2011, but the trend was reversed in the last 3 years. The number of articles from the other three countries (the UK, Japan, and Germany) remained relatively stable. In 2013, China surpassed the UK and approached Japan with respect to the number of hematology articles published. There is no doubt that the USA is the leader in this area of research and has a much stronger research effort than the other five countries. The same pattern was demonstrated when the publication of different types of articles was analyzed. The USA was the leader in publishing each type of article, especially reviews and RCTs. A review is an attempt to summarize the current state of understanding on a specific topic and make comments, and is usually written by a leading expert in the area [5]. A RCT is the gold standard for a clinical trial, and is often used to determine the effectiveness of various types of medical interventions. A RCT may provide information about adverse effects, such as drug reactions. A RCT is considered to be the most reliable form of scientific evidence in the hierarchy of evidence, and influences healthcare policy and practice. The results herein demonstrated that the USA has made the greatest contribution in the field of hematology. Specially, the number of meta-analyses published from China approached the number of meta-analyses published from the USA, which can be explained by the rapid development of evidence-based medicine in China.

With respect to the number of articles, China has made tremendous progress. The GDP of China ranks second in the world behind the USA. Between 2000 and 2012, the amount of research spent in China increased from $10.8 billion to $168 billion. According to an OECD estimation, the Chinese government invested 1.98% of the GDP in research in 2012 [6], and the amount announced by the government may reach 2.5% in 2020 [7]. Various types of medical research-funded projects also increased considerably in the past decade. For example, the Department of Health Sciences affiliated with the National Natural Science Foundation of China was founded in 2009 and there is a special office dedicated to funding respiratory, hematology, and circulatory system research. In fact, funds from this office increased significantly from 228.81 million yuan in 2010 to 591.09 million yuan in 2013. Furthermore over the past decade, the number of Chinese scientific and technical personnel experienced the same rapid growth. All of those factors have greatly promoted Chinese research in the field of hematology.

The IF of an academic journal is a measure reflecting the average number of citations to recent articles published in the journal. The IF is frequently used as a proxy for the relative importance of a journal within its field; journals with higher IFs are deemed to be more important than journals with lower IFs. Despite considerable criticism regarding the IF, the IF is universally accepted as the most convincing index for quality evaluation of journals [8,9]. In the past 10 years, the cumulative IFs of articles published in the USA were several times higher than the other countries. With respect to the median IF of published articles, the UK led the countries surveyed, while the articles published from Japan, China, and South Korea were significantly lower than articles published from Europe and USA; these findings did not change significantly in 2009–2013. When comparing the distribution of publications related to the IF, articles published from Europe and USA were shown to be mostly published in the top 25% of journals; however, China lagged behind and ranked last with respect to publications in the top 25% of journals. This is an important method regarding the evaluation of publication quality, and the result may alert Chinese scientists in this regard. This phenomenon, at least in part, may be a reflection of China, Japan, and South Korea being non-English speaking countries. Indeed, European and USA researchers may not pay close attention to scientific findings published in languages other than English.

Despite the rapid growth in the number of articles from China, the quality was not satisfactory. This may be associated with the current imperfect evaluation system on research performance that exists in mainland China [10,11], which enforced researchers to pay more attention to quantity rather than quality. The citation reports and the number of publications in the top 10 journals further support the above conclusions.

There were several limitations in the present study. Even though the journal list was generated based on the hematology category in SCIE subject categories, there may be excellent hematology journals that were not included by SCIE. Second, the publication of some international collaborative studies may have only listed one address for all authors. Therefore, when included in this study, the contributions of other countries were ignored. Third, there are some hematology-related articles published in general medical journals, which likely affected our results.