Figure 1. Markov decision process model for order of deceased donor and living donor transplantation among pediatric kidney transplant candidates.

Patients entered into the Markov model must decide whether to utilize their single available living donor for primary living donor transplantation. Declining patients start their first simulated month in the waitlist state (W), and their Markov state over the subsequent 240 months is determined by the probability of deceased donor kidney transplantation (W2T^D) or death (W2D). Patients who choose to utilize their living donor undergo immediate living donor transplantation, and their subsequent states are determined by the probability of death (T^L2D) and the probability of graft loss (T^L2W), necessitating a return to dialysis and immediate relisting for deceased donor retransplantation. Following deceased donor transplantation, a patient’s subsequent states are determined by the probability of death (T^D2D) and the probability of graft loss, necessitating either living donor retransplantation (shown with dashed line, if available) or rather a return to dialysis and immediate relisting for deceased donor retransplantation (T^D2W) if one’s living donor is no longer eligible for donation. After patients experience two graft failures, subsequent states are determined by the probability of death (GF2D).