Introduction: The legal status and environmental factors can influence the number of organ transplants. The annual number of pancreas transplants in Japan has changed much with the legal revision in 2010 and the COVID-19 pandemic beginning in 2020. We therefore describe the changes in annual transplant numbers and their outcomes in Japan.

Methods: The 437 patients who had received pancreas transplants were divided into 2 groups according to when pancreas transplantation was performed: era 1 (before the legal revision, 2000-2009, n=85) and era 2 (after the legal revision, 2010-2019, n=352). The patient and pancreas graft survival were then compared. In addition, the annual number of pancreas transplants performed during the COVID-19 pandemic was also reviewed.

Results: While the annual number of brain-dead donors was less than 10 in era 1, it significantly increased to over 50 cases in era 2, with >30 pancreas transplants being performed per year. The rate of utilization of pancreata from brain-dead donors dramatically decreased in era 2; while the utilization rate was 100% in 2009, the final year of era 1, the utilization rate was 50% in 2018 and 2019, respectively, the last two years of era 2. More stringent donor selection resulted in the median age of donors for pancreas transplantation being 49 years old in era 1 and 43 years old in era 2, showing that donors were significantly younger in era 2 than in era 1 (P<0.001). The patient survival after pancreas transplantation showed no significant difference between eras 1 and 2. In contrast, after a propensity score-matched analysis, the death-censored pancreatic graft survival at 1, 3, and 5 years after pancreas transplantation in era 2 was 94.9%, 92.0%, and 92.0%, which, while lacking significance, tended to be better than the values of 90.5%, 83.1%, and 78.2%, respectively, in era 1. As mentioned above, the revision of the law in Japan positively influenced pancreas transplantation; however, the COVID-19 pandemic has decreased brain-dead organ donations by about two-thirds, and pancreas transplants have decreased, numbering 28, 23, and 30 cases annually in 2020, 2021, and 2022.

Conclusions: Revising the law on donating brain-dead organs increased the number of pancreas transplants, and technical improvements in surgery due to increased experience with performing pancreas transplants may help improve the pancreatic graft survival. However, the COVID-19 pandemic has decreased the number of brain-dead organ donations since 2020, thereby decreasing the annual number of pancreas transplants as well.