A multiple methods approach to determine adherence with prescribed mycophenolate in children with kidney transplant.

Aims The aim of this study was, to use a multiple methods approach, including, for the first time, dried blood spot (DBS) sampling with population pharmacokinetic interpretation, to assess adherence to mycophenolate in children with kidney transplant. A second aim was to identify patient/parental factors that influenced adherence and to link adherence behaviour to clinical outcomes. Methods A convenience sample of 33 children with kidney transplant (age <= 18 years) who had been prescribed mycophenolate for at least 3 months were recruited from participating outpatient clinics in the UK and Jordan. Medication adherence was determined via self-report questionnaires, medication refill data from dispensing records, and via mycophenolic acid concentrations in plasma and DBS samples obtained from children during a clinic visit. Results Through triangulation of results from the different methodological approaches a total of 12 children (36.4%) were deemed to be nonadherent with their prescribed mycophenolate treatment. Logistic regression analysis indicated that nonadherence was significantly associated with the presence of mycophenolate side effects. Poor adherence was positively linked to measures of poor clinical outcomes (hospitalisation and the need for kidney biopsy). Conclusions Despite the imperative regarding medication adherence to help prevent organ rejection, a significant proportion of children are not fully adherent with their therapy. Side-effects appear to be an important factor leading to nonadherence. Measurement of mycophenolate in DBS samples, coupled with the use of population pharmacokinetics modelling, was a convenient direct approach to assessing adherence in children with kidney transplant and has the potential to be introduced into routine practice.