A DISCRETE CHOICE EXPERIMENT (DCE) ON PATIENTS' TIME AND RISK PREFERENCES IN KIDNEY TRANSPLANTATION: PATIENTS' AGE AND WILLINGNESS TO WAIT (WTW) FOR BETTER ORGANS

Background: WTW from the perspective of the patients themselves is unknown. We run a DCE to elicit patients’ preferences, namely their risk attitude and time discounting. Method: From April 2015–February 2017, 211 candidates (mean age 50 yrs) on the waiting list for kidney transplant were interviewed. 16 pairs of alternatives were proposed: alternative differs along 4 attributes, waiting time, graft survival, infectious risk, neoplastic risk. Time attribute has 4 levels (6, 12, 36, 60 months), survival 3 levels (10, 15, 20 years) and both risks 2 levels (standard/increased). A mixture logit model was used to retrieve individual WTW and compare the entire distribution of preferences by different age groups. Results : Older patients are willing to wait much less than younger candidates for extra year of graft survival. After age of 37, the effect of age on WTW for graft survival becomes negative. WTW for an extra year of graft survival is lower for females compared to males by about 1 month. The result is robust to a number of different model specifications. For standard infectious risk, females are willing to wait 8 months more compared to males. Having completed high school education compared to elementary education lowers WTW to avoid standard infectious risk by 7 months. No statistically significant difference in term of risk attitude among different age levels can be detected. Older patients have more heterogeneous preferences in terms of risk attitude than younger patients: for them the benefit of reducing waiting time and the potential cost of receiving an organ with augmented risk, are larger compared to the younger patients and this induces heterogeneity. Conclusions: Our experiment suggests that pre-emptive transplantation with ECD to elderly patients maximizes the efficiency of allocation in terms of overall years of graft survival for transplanted organs and the patients’ welfare.