Is Non-Adherence Associated with Adverse Outcomes in Kidney Transplant Recipients? The Role of Non-Adherence as a Risk and Predictor Factor for Graft Loss and Death.

Introduction:  Non-adherence in kidney transplants is diversely defined. Immunosuppression non-adherence (INA) is the most used definition and has been associated with graft loss and acute rejection. But INA assesses only one fraction of adherence. Therefore, we analyzed the association of a holistic non-adherence definition with transplant outcomes and compared its prediction performance with other definitions. Methods:  We retrospectively included 739 kidney recipients between 2019 and 2021. We evaluated holistic non-adherence (HNA), suboptimal-immunosuppressor levels (SIL), appointment non-adherence (ANA), procedure non-adherence (PNA) and INA. The main outcomes were graft loss, graft rejection, and mortality. A backward logistic regression was performed estimating adjusted and un-adjusted odds ratio (OR) for each outcome. Finally, we compared the non-adherence definitions' prediction for the main outcomes using the area under the curve. Results: HNA was present in 28.7% of patients. Non-adherent patients had an adjusted OR of 2.66 (1.37-5.15) for mortality, 6.44 for graft loss (2.71-16.6), and 2.28 (1.15-4.47) for graft rejection. INA and PNA presented a moderate discrimination for graft loss and HNA and ANA mild-to-moderate discrimination for graft loss and death. Conclusion: Holistic non-adherence was associated with worst outcomes in kidney recipients and had a significant prediction performance for graft loss and mortality.