Introduction: Advances in pediatric liver transplantation have led to an increasing number of patients reaching adolescence in whom poor adherence rate increases, becoming a prevalent risk factor for rejection and other adverse outcomes. Being a modifiable factor, its monitoring is a common practice in long-term follow-up and interventions on it are a priority for transplant programs. However, improvements in adherence do not correlate with long-term clinical results, these being the objective variables of graft functionality. The objective of this study is to correlate adherence measurement by both objective and subjective methods, with graft dysfunction and/or pathological liver biopsy, and to measure long-term clinical results as ideal transplant (single transplant, monodrug, no clinical complications associated with immunosuppression and normal growth).

Methods: Measurement and analysis of adherence using objective (variability in drug levels, >2 SD) and subjective methods (SMAQ questionnaire and medical impression) in 62 adolescents with liver transplantation who came for a follow up visit from August 2019 to March 2020 at Garrahan Hospital. Association was searched between the different adhesion methods and chronic graft injury (defined as three months or more of increased transaminases and/or pathological liver biopsy -rejection or fibrosis >2 on the Knodell-Ishak scale) using univariate logistic regression models. A p<0.05 was considered as significant, and STATA 15 was used.

Results: Of the patients surveyed, 50% were female, median age of 15.8 years (10.6-18.5), 10 patients received a retransplant (16%) and 40 had more than 10 years post-transplant (64.5%). 55.7% lived in CABA/AMBA and 40.9% in the rest of the country. No statistically significant association was seen between any of the adherence measurement methods with graft dysfunction and/or pathological liver biopsy (p 0.66 and 0.53 for variability, 0.96 and 0.11 for SMAQ questionnaire and 0.35 and 0.19 for subjective opinion). A total of 13 patients (21%) with ideal transplant results were obtained with a mean follow-up of 12.37 years.

Conclusion: With the data collected, it is not possible to correlate in a statistically significant way the measurement of poor adherence with graft dysfunction and/or pathological biopsies. Potential biases of this study are sample size, follow-up time and the population studied (adherent group that attends control). However, since variability is an objective method and is related to adverse effects related to immunosuppression, we consider that drug measurement and its variability is the best method. Measurement of adherence is necessary since it allows evaluating interventions aimed at improving it, despite the fact that it is not directly related to clinical results. The focus on long-term transplant care has shifted to long-term consequences of immunosuppressive treatment, and it should be measured with objective variables (“ideal transplant”).