Application of self-reporting, clinicians’ assessment, and tacrolimus trough levels in evaluating adherence to immunosuppressive therapy in kidney transplant recipients. A cohort study

Abstract

Objectives The novel immunosuppressive therapy has prolonged graft survival after transplantation. Immunosuppressants are drugs with narrow therapeutic index and intraindividual pharmacokinetic variability. Nonadherence to immunosuppressive therapy will lead to over or under-exposure of immunosuppressants leading to graft rejection. Methods A cohort study was conducted on kidney transplant recipients from the nephrology clinic and therapeutic drug monitoring unit. Patients were asked to self-report their medication adherence using a self-assessment tool. Assessment by the clinician and variation of tacrolimus (C trough) levels were evaluated. Tacrolimus concentration and kidney functions were measured prospectively to correlate with patients' adherence. The variation of Tacrolimus (C trough) levels between 20-43 % was classified as medium and above 43 % as poor adherence. Results Among 58 participants, 33 (56.7%) were females. The maximum number of years attained after transplantation was 17, with a median duration of 5 years. On the self-reporting scale, 47.0% of adherence was due to fear of graft rejection. Among nonadherence, 77.4% had their immunosuppressive therapy two hours before or after the prescribed time. Based on the clinician score, 39 (67.2%) and 42 (72.4%) cases were identified as nonadherence and having tacrolimus C trough level above 20 % respectively. The median (95% CI) serum creatine and blood urea nitrogen levels in the medium category were 1.23 mg/dL (1.2-1.4) (P = 0.009) and 28.3 mg/dL (26.4-36.4,) (P = 0.021) respectively. The corresponding values for poor adherence were 2.5 mg/dL (1.6-3.5,) (P = 0.03) and 43.0 mg/dL (35.5-78.0) (P = 0.01). Conclusions The fear of allograft rejection is linked with a better adherence rate. Nonadherent transplant recipients required close observation and frequent monitoring of immunosuppressant levels for graft survival.