Reassessing Simultaneous Pancreas-Kidney Vs. Kidney Transplant Alone: A Propensity-Weighted Analysis of Survival and Morbidity

Abstract

This study compares outcomes between Simultaneous Pancreas-Kidney Transplantation (SPKT) and Deceased Donor Kidney Transplantation (DDKT) in recipients with diabetes, assessing survival benefits against surgical and immunological risks. We analyzed Scientific Registry of Transplant Recipients data (2014-2023) to assess patient and kidney graft survival. Overlap propensity score weighting was applied to adjust for group differences. Kaplan-Meier and Cox proportional hazards models were used to estimate survival outcomes in unadjusted, covariate-adjusted, and weighted analyses. Among 22,545 recipients with diabetes (25% SPKT), those receiving SPKT were younger (41 vs. 52 years), predominantly non-Hispanic white, had type 1 diabetes, lower BMI, shorter dialysis duration, and higher preemptive transplant rates (all p<0.001). Overlap-weighted (ow) analyses showed no significant differences in 5- and 10-year patient (SPKT: 86%, 71%; DDKT: 87%, 74%) and kidney graft survival (SPKT: 80%, 66%; DDKT: 83%, 62%). SPKT recipients with graft survival at 1 year experienced higher one-year treated rejection (owOR: 2.80, 95% CI: 1.75-4.49) and hospital readmissions (owOR: 2.05, 95% CI: 1.62-2.60). However, among recipients with type 1 diabetes and BMI <30, SPKT was associated with lower mortality. After adjustment for selection bias, SPKT did not improve long-term survival compared to DDKT and was associated with greater early morbidity.