Evaluation of Medication Adherence Over a Decade Following Kidney Transplantation: Integration of Biological and Self-Reported Data

Background This study aims to determine the course of immunosuppressive medication adherence (MA) in individuals who have undergone kidney transplantation for over a decade and to identify the demographic and clinical factors affecting this adherence. Methods This retrospective and cross-sectional descriptive study evaluated the biological adherence of 103 kidney transplant recipients (KTRs) at 12 different time points using tacrolimus and cyclosporine blood levels. Self-reported adherence was assessed via the immunosuppresive therapy adherence. Associations between adherence and demographic and clinical variables were also analyzed. Results The mean time since transplantation was 11.77 ± 1.46 years. Biologically, 43.3% of patients had low MA. In contrast, self-reported adherence was 82.52%. No statistically significant correlation was found between biological and self-reported adherence outcomes. Patients with low biological adherence presented increased blood urea nitrogen (BUN) levels at 6 months and 9 years post-transplant. Similarly, patients with low self-reported adherence had increased BUN levels at 10 years. Self-reported adherence scores were significantly lower among patients with a history of graft rejection (p < 0.001). No significant associations were found between MA and variables such as sex, donor type, or age (p > 0.05). Conclusions Immunosuppressive MA in KTRs may fluctuate over time, and varies according to the assessment method. The combined and time-consuming use of biological and self-reported measurements may contribute to a more accurate determination of the risk of non-adherence. Individualized follow-up and support programs should be developed, taking into account the multidimensional factors that influence adherence.