Scientific publications in critical care medicine journals from East Asia: A 10-year survey of the literature

Objective: The quantity and quality of publications in critical care medicine from East Asia haven’t been reported. This study aimed to investigate the contribution of publications from East Asia. Methods: Articles from China, Japan and South Korea in 2005 to 2014 were retrieved from Web of Science and Pubmed. The number of publications, impact factor, citation, and article types were analyzed. Results: There were 3076 publications from East Asia (1720 from China, 913 from Japan, and 443 from South Korea). There were a significant decrease in publications from Japan (p = 0.024) and significant increases from China (p = 0.000) and South Korea (p = 0.009). From 2006, the number of articles from China exceed Japan. China had the highest total impact factor (6618.48) and citation (18416), followed by Japan (4566.03; 15440) and South Korea (1998.19; 5599). Japan had the highest mean impact factor (5.00) and citations (16.91), followed by South Korea (4.51; 12.64) and China (3.85; 10.71). Conclusions: China and South Korea`s contributions to critical care medicine had significant increases during the past 10 years, while Japan had a significant decrease. China was the most productive region in East Asia since 2006. Japan had the highest quality research output.

medical fields. [4][5][6] However, to our knowledge, the quantity and quality of East Asian research production in critical care medicine have not been reported. Therefore this study aimed to investigate the contributions of articles from East Asia to critical care medicine during a 10-year period.

Search strategy:
A total of 27 journals were identified from the "critical care medicine" category of the 2013 Journal Citation Reports (JCR). 7 We only included the journals published in English, and therefore non-English-language journals were excluded. Because this analysis was a 10-year literature survey, the journals that have been cited by JCR only in recent years, not including the full 10 years of our survey, were excluded also. Finally, 21 journals were included, as listed in Table-I. In April, 2015, literature search was performed using Web of Science and Pubmed. Articles published between 2005 and 2014 in these 21 journals were identified. Only original articles and reviews were included. Letters, editorial material and correction were excluded. The "Reprint Address" of each article was considered as the source region. 8,9 No articles was collected from North Korea, Mongolia, and Macau during the study period, so the articles from Japan, South Korea and China (including ML, HK, and TW) were selected accordingly. Data extraction: Two reviewers independently conducted study selection and data extraction. Disagreements were resolved by discussion. The number of publications were used to evaluate the quantity of research output. The quality of research was assessed by impact factor (IF) and citation reports. The total number of articles, the total and mean impact factor, and the total number of citation and mean citation per article were collected. In order to analyze the article types, the number of clinical trials (including cross-sectional and prospective cohort studies), randomized controlled trials (RCTs), meta-analyses and case reports were compiled using the publication type categories of the Pubmed database. In addition, articles published on the high-impact journals (IF>5) were generated, and the five most popular critical care medicine journals of the three countries were also determined according to the number of publications. Statistical analysis: Descriptive statistics (eg, total, mean) were mainly used in this study. Regression analysis was used to determine significant changes in time trend between 2005 and 2014. Data analysis was performed using statistical software SPSS version 19.0 (SPSS Inc., Chicago, IL, USA), and p < 0.05 was considered statistically significant.   Table-II). However, Japan had the highest mean impact factor of 5.00, followed by South Korea (4.51), and China (3.85) ( Table-III). Among the three regions of China, ML had the highest total impact factor (3252.99), while HK had the highest mean impact factor (4.60) ( Table-II and Table-III). Citation: The total citation of the published articles from 2005 to 2014 in China (18416) were higher than that in Japan (15440) and South Korea (5599) (

DISCUSSION
East Asia is increasingly important to the world due to its rapid developments in economy, science and technology. However, the status of scientific research on critical care medicine from East Asia have not been investigated. Publication is an important indicator of the advancement of scientific research. It has been widely used to study the contribution of East Asia to the whole world. [4][5][6] This study gives an insight into the research output from East Asia in the field of critical care medicine.
Some East Asian regions, especially Japan, played an important role in the scientific and medical research in the past decades. However, a significant decrease trend of Japanese scientific publications in the field of critical care medicine was observed in our study. This trend was also found in other medical fields. 4,10,11 There may be several reasons. First, the recession of Japanese economy in the past decades might lead to the decrease of financial funding support to medical research and subsequent the decrease of publications. 4 Second, from 2004, the program of compulsory training on Japanese medical residents might induce the decrease of scientific research power in the medical universities. 10 The progress of research productivity may mirror the financial status of the countries, especially for China. Growing contribution to scientific research from China has been proved in many biomedical fields. [4][5][6]8,9,11 It also holds true for the field of critical care medicine. China published the largest number of clinical trial, meta-analysis, RCT and case reports, indicating a comprehensive progress in the field of critical care medicine. There are several possible reasons for this trend. First, the rapid economic development of China may lead to the increasing funding in critical care medicine. 8,9 Second, China has an advantage in recruitment of participants in medical research due to the largest population in the world. 8,12 Third, clinical trials performed in China may be much less expensive than other developed countries. 4,12 Therefore China may give more contribution to critical care medicine in the future.
In this study, articles published by China had the greatest number of total impact factor and total citation. This result suggests that China has the greatest overall impact in critical care medicine in East Asia. One of the main reasons may be that China published the most articles. When mean impact factor and mean citation were used to assess the quality of publication, Japan ranked the highest, indicating that Japan published more high quality research than China and South Korea. The most popular journal for Japan was Chest, the most popular journal for South Korea was Resuscitation, and the most popular journal for China was Shock. This finding indicate that different countries may have different research power. Chest appeared in all the top-5 journals in the three countries. It suggests the important influence of this journal in East Asia.
There are some limitations in this study. First, only impact factor and citation were used to evaluate the papers in this study, despite there were many measurements, such as Scimago and H index. Second, the journals were selected from the critical care medicine category of the JCR, but some journals in general medicine journals, such as some high ranked journals, also published some articles related to critical care medicine. Nevertheless, the journals included in this survey represent the major international journals devoted to the discipline of critical care medicine.

CONCLUSION
The number of articles increased significantly in both China and South Korea during the past 10 years, while decreased significantly in Japan. From 2006, China was the most productive region in East Asia. Japan had the highest quality research output according to mean citation and mean impact factor per article.

Declaration of interest:
None.