Publication Trends in Physical Medicine and Rehabilitation in Japan from 2001 to 2019.

Objectives: The aim of this study was to examine, using PubMed, the number of articles in the field of physical medicine and rehabilitation medicine originating in Japan, especially those containing high-quality scientific evidence (randomized controlled trials [RCTs], systematic reviews, meta-analyses) and those published in high impact factor journals.

Methods: We searched the PubMed database to identify articles, RCTs, systematic reviews, and meta-analyses from Japan covering physical medicine and rehabilitation published between 2001 and 2019; we then calculated the proportion of articles from Japan. Additionally, using Journal Citation Reports, we selected the top ten highest impact factor journals on "Rehabilitation" each year between 2001 and 2019. For each year, we searched PubMed for the total number of articles in these top ten journals and for articles originating in Japan. The Cochran-Armitage test was used to evaluate the change in the proportion of publications from Japan over time.

Results: The proportion of articles on physical medicine and rehabilitation originating in Japan increased from 2001 to 2019 (P<0.0001). An increase in the percentages of systematic reviews (P=0.046) and meta-analyses (P=0.0013) originating in Japan and a decrease in the percentage of original articles published in the top ten highest impact factor journals were demonstrated (P=0.002). However, there was no change in the percentage of RCTs from Japan over time (P=0.055).

Conclusions: Our findings suggest that the proportion of articles from Japan containing high-quality scientific evidence is increasing. However, there is a need to expand the support system for research while considering the quality of research.