Distribution and retention trends of physician-scientists in Japan: a longitudinal study

BACKGROUND: Physician Scientists (PSs) play a significant role in medical science because of their clinical practice and research expertise. Although it is important to analyze the distribution and retention trends in the number of PSs in Japan, research on this topic has been insufficient. Thus, the purpose of this study is to analyze PSs distribution and retention trends, identify factors related to their retention, and consider the policy implications. METHOD: I analyzed individual data from 1996 to 2016 from a national census survey that had been administered by the national government of Japan every 2 years. The number of PSs in 1996 and 2016 were 4930 (2.1% of all physicians) and 5212 (1.6%), respectively. I conducted a descriptive analysis and identified retention trends. I then used a multivariable logistic regression analysis to identify the factors related to the retention of PSs. RESULTS: Between 1996 and 2016, the total number of PSs in Japan increased by 6%. The number of PSs aged 39 years or younger decreased by 48%, while those aged between 55 and 69 increased by 91%, indicating a notable decrease in the number of PSs under the age of 39. From 2014 to 2016, the annual retention rate of PSs was estimated to be 75.5%, which represented a low and stable rate compared to other physicians over the study period. The odds of continuing to practice as a PS were significantly higher for those who have between 15 to 29 years of experience after qualification as a physician. CONCLUSION: This study indicates that it is likely for the total number of PSs to decrease in the future. Although the Japanese government has implemented various measures to retain PSs, these have not been effective. Possible new interventions to address this problem include increasing the knowledge of medical students and younger physicians of the role of PSs and the benefits of a career as a PS, providing specific career paths for PSs, securing specific positions for PSs, and increasing the compensation for PSs.