Factors Associated with Immunosuppressive Adherence in Liver Transplant Recipients Treated with Once- and Twice-Daily Tacrolimus.

Background and Objectives: Immunosuppressive medication adherence is essential for maintaining graft function and long-term survival after liver transplantation, yet adherence may be influenced by treatment complexity, psychosocial burden, and post-transplant medication changes. Although once-daily tacrolimus (TAC) has been proposed as a regimen-simplification strategy, the relationship between TAC dosing frequency and adherence in liver transplant recipients remains insufficiently clarified. This study aimed to evaluate the association between TAC dosing frequency and medication adherence in liver transplant (LT) recipients and to compare psychosocial characteristics, immunosuppressive treatment patterns, and post-transplant medication stability between dosing regimens. Materials and Methods: This cross-sectional study included 231 LT recipients followed at the Inonu University Liver Transplantation Institute. Patients were categorized according to TAC dosing regimen as once-daily (n = 121) or twice-daily (n = 110) use. Data were collected through structured telephone interviews using the validated Immunosuppressive Medication Adherence Scale (IMAS), together with demographic, clinical, psychosocial, treatment-related, and socioeconomic variables. Results: Most demographic and anthropometric characteristics were comparable between once-daily and twice-daily TAC groups, and mean IMAS total scores did not differ between groups (p = 0.785), indicating similar levels of self-reported medication adherence. In contrast, anxiety or depressive disorders were more frequent among once-daily TAC recipients (p = 0.045), and everolimus use was higher in this group (p = 0.025). Frequent post-transplant immunosuppressive medication changes were markedly more common among once-daily recipients (p < 0.001), and low monthly income was also more prevalent (p = 0.002). In subgroup comparisons, lower IMAS scores were observed in recipients experiencing frequent medication changes (p = 0.011) and in those who had not received medication-related education from healthcare professionals (p = 0.013). In univariate general linear model analyses, IMAS scores were not associated with TAC dosing regimen or sociodemographic characteristics, whereas frequency of immunosuppressive medication changes (p = 0.012), source of support for medication management (p = 0.048), and receipt of medication-related education from healthcare professionals (p = 0.036) were significantly associated with IMAS scores. In multivariable linear regression, frequent medication changes (p = 0.017), source of support for medication management (p = 0.028), and receipt of medication-related education (p = 0.019) remained independently associated with IMAS scores. Conclusions: TAC dosing frequency was not associated with self-reported medication adherence in LT recipients. Lower IMAS scores were associated with frequent post-transplant immunosuppressive medication changes, the need for external support in medication management, and lack of medication-related education from healthcare professionals. Compared with the twice-daily group, once-daily TAC recipients more frequently reported anxiety/depressive disorders, everolimus use, frequent medication changes, and low income, despite similar IMAS scores.