Does graft implantation sequence affect post-transplant outcome in simultaneous pancreas-kidney transplantation? An analysis of a nationwide registry in Japan

Purposes: Simultaneous pancreas-kidney transplantation (SPK) is an effective treatment for type 1 diabetes and end-stage renal disease. However, whether the graft implantation sequence influences the outcomes remains unclear. This study aimed to clarify the impact of implantation order on graft and patient outcomes using data from the Japanese Pancreas Transplant Registry. Methods: We retrospectively analyzed consecutive patients with SPK during the study period. Patients were categorized into pancreas-first (P-first) or kidney-first (K-first) groups based on the ischemic time of each graft. The outcomes assessed included graft loss, graft survival, and patient survival. Kaplan-Meier and multivariate Cox regression analyses were used to compare the groups. Subgroup analyses were also performed, including assessments of transfer time. Results: Among 449 SPK recipients, 346 were in the K-first group and 103 in the P-first group. No significant differences were observed between the groups with regard to pancreatic or kidney graft loss, graft survival, or patient survival. These findings remained consistent across all subgroup analyses and in models that used transfer time as a continuous variable. Conclusions: The graft implantation sequence did not significantly affect graft or patient outcomes following SPK. The order can be chosen based on surgeon preference or institutional protocols, without compromising the prognosis.