Kidney Exchange Programs: Incentives for Compatible Couples

The increasing number of kidney diseases and the shortage of kidneys for transplantations are critical points for the public health in the world and in Italy as well. Dialysis procedures are helpful treatments, but they do not represent the optimal choice in the long term, neither for the costs nor for the health of the patients. The waiting list for an organ from a deceased donor require a lot of time and cannot be predicted. Anyway, the transplantation from living donor is the best choice, ceteris paribus. There are incompatibilities among the people that hinder the transplantations and others that can be overcome only through extremely expensive. Thanks to the kidney exchange programs, it is possible to find the best matches for the couples, but it is important which objectives need to be prioritized. Through the counterfactual exercise conducted on the pool of transplanted couples and incompatible couples in Padua, it has been possible to verify the efficiency of a proposal for an exchange program. The three categories of couples (compatible, half-compatible and incompatible) have different urgencies and the likelihood of participating to a kidney exchange program is not the same. The priority should be given to the incompatible couples, who do not have a viable alternative for the transplantation but are forced to wait for a deceased donor with a compatible kidney. They should be the first target of the exchange programs. The half-compatible couples can be transplanted after desensitization, which is an expensive treatment, and does not guarantee the same expected outcome of a compatible kidney. Therefore, half-compatible couples should be favored in finding a match that avoids desensitization. The objective of avoiding the HLA desensitization is prepended to the objective of avoiding the ABO desensitization due to the higher graft reject. The compatible couples are the ones with less incentive to participate to such programs because they may undergo transplantation, but there are factors that suggests that they may benefit from finding another match. For instance, a younger organ or a more balanced BMI ratio between donor and recipient are factors that improve the expected outcome. The threshold of the LKDPI improvement should balance the expected benefits and the risk of participating without finding a better match, that is the worst option. The Living Donor Kidney Profile Index (LKDPI) is a measurement that assist in the prediction of the outcome of a transplantation. It is useful to classify the compatible couples and understand their likelihood to take part to a kidney exchange program. A low value of the LKDPI means a lower probability of finding a better match. Consequentially, a high value implies a high probability of finding a better match. For this reason, it is useful to create four categories for the compatible couples, according to their LKDPI score. To each category there is a probability associated, which represent the likelihood of participating or not to a kidney exchange program. It is downward according to the LKDPI of the couple. The participation of all the compatible couples is not an optimal choice because a large part will not find a better match and will have to bear the extra costs of the dialysis with all the psychological and physical costs related. The inclusion of the categories is finalized to limit this time waste. The results of the counterfactual exercise confirmed that the participation of the compatible couples is fundamental because it enlarges the number of couples participating. With a larger pool, it is easier to find a compatible match for the incompatible couples, that can finally undergo the transplantation, and for the half-compatible couples, that can avoid the desensitization processes. Thus, the participation of the compatible couples is fundamental for the right functioning of the kidney exchange programs.