Introduction: After several years of growth in many pancreas transplant programs, the United Network for Organ Sharing (UNOS) database reports a decline in transplant numbers in the USA. This trend urges for an evaluation of the transplant numbers and scientific productivity in the Eurotransplant (ET) region and the UK.
Materials and Methods: We used the UNOS database, ET registry, and the UK transplant registry to describe the development of pancreas transplantation rates between 1997 and 2016. Next, we used the Web of Science database for a bibliometric analysis of scientific publications in the field of pancreas transplantation. Transplantation rates were adjusted for changes in population size in the different regions. We calculated graph specific slopes and annual average changes to assess trends in pancreas transplantation and scientific publications rates.
Results and Discussion: For the USA and the ET region, from 2004 the trend in transplant numbers changes from growth to decline, with highest annual transplant numbers of 5.1 per million inhabitants in the USA and of 2.4 per million in the ET region. Between 2004 and 2016 the average annual decline rate per million inhabitants was 3.3% for the USA and 2.5% for the ET region. In the UK, yearly transplant numbers show a growth until 2009, with 3.6 transplants per million inhabitants, after which the numbers showed an average annual decline of 1.0%. Following this trend, publications in Q1 journals showed an annual average change of +0.1%, ‑2.1% and +20.1%, before 2004, and a change of -4.1%, -3.8% and -5.45%, between 2004 and 2016, for respectively worldwide, the USA and the ET publications (Figure 2).From the 10 publications with the highest impact in this field, 9 publications were from USA-based authors and 5 out of 10 used data from the UNOS database, none were based on European studies.
Conclusions: Adjusting pancreas transplantation rates for changes in population size showed a clear decline in transplant numbers in both the USA and ET region, with first signs of a decline in the UK. Following this trend, the number of scientific publications declines worldwide and specifically in the USA and ET region. With the UNOS database in mind, we advocate for a renewed European pancreas collaboration to evaluate the decline in transplant numbers and to establish a comprehensive database for multivariate analyses of pancreas transplant outcomes. A European registry is the key to a reliable transplant trend evaluation and will support transplant programs in their progress to better outcomes.