Medication adherence in pediatric transplantation and assessment methods: a systematic review

Background: Medication adherence is a major concern in public health. It is fully established that immunosuppressive therapy (IT) and concomitant medications affect transplant outcomes in the pediatric population, showing interest in adherence to this therapy. The aim of the present review was to report on medication adherence in pediatric population post-transplantation. This will enable us to know the situation in this particular population. Methods: A literature search was performed using the MEDLINE database. Studies that were published from January 1999 to January 2016 in English language and which investigated medication adherence in pediatric transplantation were included. The type of organ and the methods used to assess medication adherence were studied. Results: A total of 281 records were identified, from which 34 studies were selected: 38% (n=13) on kidney transplantation, 32% (n=11) on liver transplantation, and 23% (n=10) on the transplantation of other organs. Medication adherence was found to be lower than 80% in two-thirds of the studies (64%), and varied from 22% to 97%. This wide range was explained in part by the important heterogeneity of assessment methods among studies. The methods used were objective, non-objective, or combined both types. Most studies did not fully describe the data collected: the time since transplantation, the period over which adherence was assessed, the population, the medications, and the threshold discriminating adherence and non-adherence. Conclusion: The present study found poor medication adherence in the pediatric population post-transplantation. There was a wide range of medication adherence, explained largely by the heterogeneity of assessment methods. Future studies must consider the characteristics of each methodology, but also the threshold defining adherence should be chosen on the basis of clinical outcomes, and describe all data collected to gain precision. To improve adherence in this population, it is essential to identify factors influencing medication (IT and concomitant medications) adherence.