Why do a pancreas and kidney transplant together show a better long term survival rate than pancreas alone?

No clear answer: It is an interesting area of investigation. One theory is the kidney and pancreas together offer a greater ability to detect rejection. There also appear to be more technical complications with pancreas transplant alone than with simultaneous kidney and pancreas.

Rejection detected: Rejection in a kidney transplant is much easier to detect than a pancreas transplant. In a simultaneous transplant both organs reject together and are treated simultaneously.

PTA: First of all, it is specifically pancreas graft survival and not patient survival, which is considered inferior. It has previously been attributed to a higher immunologic pancreaa graft loss rate when the pancreas is transplanted alone or from a different donor from the kidney. Immunologic graft loss is decreasing and so is this disparity.