Medication nonadherence (NA) continues to be a major cause of graft loss post-transplant. Several methods for prospective adherence monitoring have been described including patient interview and assessment of drug concentration blood level variability. High intrapatient drug level variability has been associated with poorer outcomes, including graft loss, following renal transplant (RTx). We sought to compare results of patient interview scores with tacrolimus (TAC) blood level variability in selected RTx recipients thought to be NA.

Methods: RTx recipients attending routine clinic visits between Feb & Nov 2015 were screened for an adherence assessment. Those with a history or recent indication of NA behavior as determined by the lead nurse coordinator were selected to undergo a pharmacist adherence assessment that included: (1) administration of the Basel Assessment of Adherence to Immunosuppressive Administration Scale (BAASIS) questionnaire and (2) assessment of TAC trough levels over the preceding 12 months. Subjects were categorized as NA or adherent according to their self-report via the BAASIS questionnaire. Any response indicating NA behavior resulted in assignment to the NA group. The coefficient of variation (CV) of TAC concentrations, defined as the standard deviation divided by the mean, was calculated to assess drug concentration variability in those prescribed TAC. The CV was compared between groups.

Results: 100 potentially NA RTx recipients underwent an adherence assessment. 69% were male, with a mean age 51.7 ± 12.7 years and mean time post RTx 3.1 + 4.6 years (median 1.5 years) 40% (40/100) were defined as NA, including 17% (17/100) who reported missing at least one dose of anti-rejection medication within the previous four weeks. 86% (86/100) were prescribed TAC and a CV was calculated. The mean TAC CV was 44.1% (range 10.1-109.6%) overall, 44.6% (range 12.2-109.6%) in the adherent group and 43.3% (range 10.1-100.0%) in the NA group (p=0.511).

Conclusion: In a select group of potentially NA RTx recipients, self-reported NA using the BAASIS questionnaire did not correlate with intrapatient TAC level variation. The lack of correlation between TAC CV and BAASIS is not clear and is currently under further evaluation.

CITATION INFORMATION: Parrish N, Kaiser T, McCann A, Aladimi J, Harris J, Govil A, Abu Jawdeh B, Mogilishetty G, Alloway R, Woodle E. Evaluation of Patient-Reported Nonadherence with Tacrolimus Level Variability in Renal Transplant Recipients. Am J Transplant. 2016;16 (suppl 3).

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