Patient and kidney transplant survival in type 1 diabetics after kidney transplant alone compared to simultaneous pancreas-kidney transplant

Background Donor and other differences mean understanding drivers of transplant survival for type 1 diabetics is challenging. We aimed to compare outcomes of simultaneous pancreas-kidney transplant over kidney transplant alone for people with end-stage kidney disease (ESKD) and type 1 diabetes. Methods We performed a population-based cohort study comparing outcomes from kidney alone and kidney-pancreas transplants using registry data. Our study population was people in Australia and New Zealand with type 1 diabetes and ESKD who received a kidney transplant in 1984-2016. Primary outcomes were time to kidney transplant failure and all-cause death. Secondary outcomes were time to cardiovascular and non-cardiovascular death. We compared adjusted survival using Cox regression (hazard ratio HR and 95% confidence intervals CI). Results Of 1295 type 1 diabetics receiving a transplant, 430 (33%) received deceased donor kidney, 172 (13%) received living donor kidney, and 693 (54%) received pancreas-kidney transplant. Compared to deceased donor kidney, pancreas-kidney recipients had 40% lower rate of kidney transplant failure (adjusted HR 0.60; 95% CI 0.45-0.81; p = 0.001) and 34% lower mortality (adjusted HR 0.66; 95% CI 0.53-0.83; p < 0.001), driven by 49% reduction in cardiovascular mortality (adjusted HR 0.51; 95% CI 0.36-0.72; p < 0.001). Pancreas-kidney recipients had similar reductions in transplant failure and mortality compared to living kidney recipients, after adjusting for transplant timing. Conclusions For people with type 1 diabetes, pancreas-kidney transplant provides improved transplant and overall survival compared to deceased donor kidney alone. Living donor kidneys may perform just as well as pancreas-kidney transplant if waiting times are short.