Multimethod Assessment of Medication Nonadherence and Barriers in Adolescents and Young Adults With Solid Organ Transplants.

Objective: To (a) examine levels of medication nonadherence in adolescent and young adult (AYA) solid organ transplant recipients based on AYA- and caregiver proxy-reported nonadherence to different medication types and the medication-level variability index (MLVI) for tacrolimus, and (b) examine associations of adherence barriers and AYA and caregiver emotional distress symptoms with reported nonadherence and the MLVI.

Method: The sample included 47 AYAs (M age = 16.67 years, SD = 1.74; transplant types: 25% kidney, 47% liver, 28% heart) and their caregivers (94 total participants). AYAs and caregivers reported on AYAs' adherence barriers and their own emotional functioning. Nonadherence was measured with AYA self- and caregiver proxy-report and the MLVI for tacrolimus.

Results: The majority of AYAs and caregivers denied nonadherence, with lower rates of nonadherence reported for antirejection medications. In contrast, 40% of AYAs' MLVI values indicated nonadherence to tacrolimus. AYAs and caregivers who verbally acknowledged nonadherence had more AYA barriers and greater caregiver emotional distress symptoms compared with those who denied nonadherence. AYAs with MLVIs indicating nonadherence had more barriers than AYAs with MLVIs indicating adherence.

Conclusions: Multimethod nonadherence evaluations for AYA transplant recipients should assess objective nonadherence using the MLVI, particularly in light of low reported nonadherence rates for antirejection medications. Assessments should include adherence barriers measures, given associations with the MLVI, and potentially prioritize assessing barriers over gauging nonadherence via self- or proxy-reports. Caregiver emotional distress symptoms may also be considered to provide insight into family or environmental barriers to adherence.