No Apparent Influence of Nonadherence on Tacrolimus Intrapatient Variability in Stable Kidney Transplant Recipients

Background: High intrapatient variability (IPV) in tacrolimus exposure has been associated with an increased risk of graft rejection and graft loss. It has been suggested that medication nonadherence has high impact on IPV. The objective of this study is to assess the relationship between tacrolimus IPV and medication nonadherence in stable kidney transplant recipients. Methods: This study was conducted within the Reducing Renal Function Deterioration trial (Netherlands Trial Register: NTR7256), which included stable kidney transplant recipients. Nonadherence was assessed quantitatively by electronic monitoring (EM) and qualitatively using the composite adherence score (CAS) consisting of patient self-reporting (Immunosuppressant Therapy Adherence Scale), a physician report, and the tacrolimus trough concentrations (C-0). IPV in tacrolimus C(0)and area under the concentration-time curves (AUCs) was evaluated at 5 and 3 sampling instances, respectively. Results: Data of 64 kidney transplant recipients (43 males, 21 females; mean age 53.6 years), mean time post-transplantation 5.4 years, were collected. Mean missed tacrolimus intake was 7% (0.3%-13.4%) based on EM, missing one intake every 2 weeks. Based on the CAS, 68.9% of the patients were categorized as nonadherent. The mean IPV was 17.9% (4.4%-65.3%) and 20.2% (2.5%-51.6%) for tacrolimus C(0)and AUCs, respectively. The nonadherence data displayed a nonparametric distribution, with nonadherence scores mostly in the lower ranges. There was no significant difference in the mean IPV between adherent and nonadherent patients. There were no differences in EM, CAS, physician report, or time-in-therapeutic range, but patients with a low AUC IPV showed a slightly higher Immunosuppressant Therapy Adherence Scale score than those with a high AUC IPV (P= 0.035). Conclusions: There was no apparent relationship between IPV and nonadherence in this motivated kidney transplant recipient population, with one missed tacrolimus dose every 2 weeks.Clinical Pharmacy and ToxicologyNephrolog

Medication non-adherence after kidney transplantation: A critical appraisal and systematic review

Medication non-adherence is one of the most important causes for shortened graft survival subsequently leading to a reduction in kidney graft survival results. Our aim was to provide an overview of its prevalence, risk factors, diagnostic methods and interventions to improve adherence in kidney transplant recipients. Therefore, we systematically searched the databases PubMed, COCHRANE Library, Web of Science and EMBASE for studies addressing "medication adherence", "compliance", "adherence", "kidney transplantation" and "life style factors". We identified 96 studies that satisfied our inclusion criteria. A problematic lack of a uniformly accepted definition for non-adherence was found, consequently leading to a wide range in non-adherence prevalence (36-55%). Using one uniformly accepted non-adherence definition should therefore be encouraged. A wide range in diagnostic methods makes it difficult to accurately detect non-adherence. Heterogeneous results of intervention studies make it difficult to select the best adherence enhancing method, challenging the battle against medication non-adherence. Literature suggests a combination of personalized interventions, based on patient-specific non-adherent behavior, to be most successful in improvement of adherence. High quality diagnostic methods and multidisciplinary, personalized interventions with focus on relevant clinical outcome are essential in overcoming medication non-adherence in kidney transplant recipients. (C) 2019 Elsevier Inc. All rights reserved.Nephrolog

Therapeutic drug monitoring of tacrolimus and mycophenolic acid in outpatient renal transplant recipients using a volumetric dried blood spot sampling device

Nephrolog