Conditional Survival for Pancreas Graft and Its Associated Factors After Pancreas Transplantation

Traditional actuarial graft survival estimates are useful in pancreas transplantation (PTx) cases. From the perspective of patients, however, a more accurate estimate is necessary to predict long-term prognosis with consideration of their specific circumstances. Graft conditional survival analysis after transplantation is useful, but no relevant studies have included PTx. This study addressed pancreas graft conditional survival (pCS) and associated factors in PTx recipients in Japan.

A total of 526 PTx cases (2000-2023) were analyzed from the Japan Pancreas Transplant Registry. In addition to unconditional actuarial survival, pCS was calculated with the Kaplan-Meier method based on graft survival to landmark times, and factors affecting pCS were investigated using a Cox proportional hazards regression model.

Unconditional actuarial 1/3/5/10-year graft survival rates were 86.6%/80.8%/76.7%/68.3% after PTx. Donor sex (male vs. female), recipient age (≤ 49 vs. ≥ 50 years), and type of PTx procedure (simultaneous pancreas-kidney transplantation vs. pancreas after kidney transplantation + pancreas transplantation alone) were significantly associated with survival. pCS increased with landmark time, indicating that posttransplant prognosis in surviving patients was more favorable than predicted at PTx. Donor sex and type of PTx procedure affected unconditional actuarial pancreas graft survival but not pCS, and recipient age influenced both pCS and unconditional actuarial pancreas graft survival.

pCS provided a dynamic perspective on long-term pancreas graft survival, demonstrating improved prognosis with extended posttransplant time. Donor sex and PTx procedure type influenced unconditional actuarial survival, but their impact diminished with time, while recipient age remained a consistent determinant of pCS.