Self-reported Non-adherence to Immunosuppressive Medication Detected by the BAASIS Predicts Allograft Rejections in Kidney Transplant Recipients.

BACKGROUND

After kidney transplantation adherence to immunosuppressive medication is crucial for graft survival and its assessment requires valid measurements. The Basel-Assessment-of-Adherence-to-Immunosuppressive-Medications-Scale (BAASIS) is a validated self-report tool to detect non-adherence, however its ability to predict clinically relevant outcomes remains to be established.

METHODS

In this prospective cohort study including 226 consecutive kidney graft recipients transplanted at the Medical University of Vienna between 2018 and 2019 the adherence towards immunosuppressive medication was monitored for 2 years after transplantation. The BAASIS was applied at the first outpatient visit and at months 3, 6, 9, 12, and 24 post-transplant to assess the implementation and persistence phase of adherence. Non-adherence was defined by any positive response to one of the BAASIS-items. The primary endpoint was biopsy-proven allograft rejection defined by the BANFF meeting report during a maximum follow-up of 4 years.

RESULTS

Of the total study cohort (median age 56 years [IQR 46-63], 75 [33%] female), 125 recipients (55%) reported non-adherence at least once. Self-reported non-adherence increased within the first three months from 11% to 31% and remained between 27% and 32% at month 6 to 24 post-transplant. Non-adherent recipients experienced more allograft rejections than adherent patients (24%, n=30 vs. 7%, n = 7; P < 0.001) during a median follow-up of 3.7 years (IQR 1.0-4.0). Using a time-dependent Cox regression model, the adjusted hazard ratio for allograft rejection associated with previously reported non-adherence was 2.90 (95% CI 1.51-5.58; P = 0.001) accounting for recipient sex, age at transplantation and history of previous transplantation.

CONCLUSION

Our findings support the clinical value of the BAASIS. Its implementation into routine post-transplant care may facilitate the identification of clinically relevant medication non-adherence, enabling timely interventions.