39 - Tacrolimus Intrapatient Variability as a Tool to Gauge Non-Adherence in Pediatric Kidney Transplant Recipients

Sunday, April 30, 2023

3:30 PM – 6:00 PM ET

Poster Number: 39
Publication Number: 39.349

Tara Gavcovich, Holtz Children's Hospital Jackson Memorial Hospital, North Miami, FL, United States; Vaka Sigurjonsdottir, University of Miami, Miami, FL, United States; Marissa JANEL. DeFreitas, University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States; Claudia Serrano, University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States; Wacharee Seeherunvong, University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States; Chryso Katsoufis, University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States; Wendy Glaberson, University of Miami Miller School of Medicine, Miami, FL, United States; Melisa Oliva, Holtz Children’s Hospital, Hollywood, FL, United States; Adela Mattiazzi, University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States; Carolyn Abitbol, University of Miami, Miami, FL, United States; Jayanthi Chandar, University of Miami Leonard M. Miller School of Medicine, Miami, FL, United States

Presenting Author(s)

Tara Gavcovich, MD (she/her/hers)

Pediatric Nephrology Fellow
Holtz Children's Hospital Jackson Memorial Hospital
North Miami, Florida, United States

Background: Long-term survival of kidney allografts is limited by rejection, a common cause of graft loss in adolescent transplant recipients. High intrapatient variability (IPV) in tacrolimus levels ( >30%) has been associated with de novo donor-specific antibody formation, increased risk of rejection and graft loss. Non-adherence is considered a common cause of high tacrolimus IPV, but has not been demonstrated conclusively.

Objective: To analyze the association between tacrolimus IPV and non-adherence in pediatric kidney transplant recipients.

Design/Methods: This cross-sectional retrospective study included kidney-only transplant recipients ≥11 to ≤23 years old, transplanted between 2007 and 2021, >10 months post-transplant at the Miami Transplant Institute, maintained on tacrolimus immunosuppression. Data was collected for eligible patients from July to November 2022. A composite adherence score ranging from 0-4 points was developed using four tools, each awarded 1 point if positive: (1) Basel Assessment of Adherence to Immunosuppressive Medical Scale (BAASIS^©) considered non-adherent if patient endorsed stopping, changing prescribed amount or missing immunosuppressive medications more than once a week; (2) provider-reported patient non-adherence; (3) patient unable to recall medication regimen; and (4) intentional missed laboratory or clinic visits. A total composite score of 1 or more was considered non-adherent. As per standard protocol, tacrolimus levels were monitored at least monthly. IPV is the coefficient of variation, calculated as standard deviation/mean tacrolimus concentration x 100%, using all available tacrolimus samples in the 6-month window prior to adherence assessment. Levels drawn while hospitalized, during sickness or mis-timed levels were excluded.

Results: 33 patients have been enrolled so far, 60.6% male, median age 16 years (IQR 13-19). Non-adherence was noted in 18 (54.5%) patients. The median tacrolimus IPV was significantly higher in non-adherent patients (32%, IQR 14-37.5) compared to adherent patients (18%, IQR 13-22), p=0.02 (Figure 1a). There was a significant positive correlation between tacrolimus IPV and BAASIS^© score alone (Pearson correlation coefficient, r=0.45, 95% CI 0.13 - 0.69), p< 0.01 and composite adherence score (r=0.56, 95% CI 0.26 - 0.76), p< 0.001, respectively (Figure 1b).

Conclusion(s): Tacrolimus IPV was significantly higher in non-adherent patients. Recognizing high IPV may be a useful tool to detect non-adherence in adolescent kidney transplant recipients at high risk of rejection, allowing for early interventions to prevent adverse graft outcomes.