Background: Non-adherence (NA) to immunosuppressive drugs is to date considered a crucial issue in kidney transplanted patients (KTRs), leading to de-novo donor-specific anti-HLA antibodies (dnDSA) development, acute and chronic rejection, and at least graft loss. However, NA assessment is challenging, often leading to underestimation in real-life settings.
Methods: NA evaluation in all KTRs referred to our post-transplantation clinic in the period between 01/01-15/07/2018 with self-report questionnaire combined to intra-patient variability (IPV) of the pivotal immunosuppressive drug (based on trough levels of tacrolimus/mTOR inhibitor).
Results: Based on both questionnaire and IPV, 86 out of the 504 tested KTRs (17%) were classified as NA. Male gender (OR, 2.0; 95% confidence interval [CI], 1.2 to 3.4), high educational level (OR for KTRs with a degree, 1.8 [95% CI, 1.0 to 3.1]), employment (OR, 2.0 [95% CI, 1.2 to 3.3]), young age at transplantation (P=0.017), longer time on the waiting list and after transplantation (P=0.027 and 0.049 respectively) were all associated with NA. High IPV was mostly documented in KTRs treated with the twice-daily formulation of the immunosuppressive drug (OR, 1.5 [95% CI, 1.0 to 2.1]) and better associated with dnDSA appearance (OR, 2.1 [95% CI, 1.1 to 3.9]).
Conclusions: NA is a significant problem, difficult to assess, and can lead to dnDSA development also in our population. Identifying risk factors for NA might be an underestimated tool to improve graft and patient outcome in KTRs.