Trajectories of Oral Medication Adherence in Youth With Inflammatory Bowel Disease

Objective: To examine longitudinal trajectories of oral thiopurine adherence over a 180-day interval in a sample of youth with inflammatory bowel disease (IBD) and to identify the role of disease activity, length of time since diagnosis, and regimen complexity in predicting adherence trajectory class membership. Method: Participants included 96 adolescents (M age = 14.32 years) with IBD. Oral medication adherence was assessed via MEMS Track Caps (i.e., an electronic monitor that allows for real-time assessment of adherence) for 6 months, after which time devices were collected and data were downloaded. Medical record reviews provided information about participants' disease activity, length of time since diagnosis, and regimen complexity (including both medications and supplements) at the time of study enrollment. Results: Two distinct adherence trajectory classes emerged: Group 1 represented those with consistently near-perfect adherence, whereas Group 2 represented those with mild nonadherence that increased with time. Complexity of medication regimen emerged as the only predictor of trajectory class, with adolescents whose regimen involved more than 1 daily medication administration time being more likely to be classified in Group 2 (i.e., the consistently near-perfect adherence group) than those whose regimen involved only 1 daily medication administration time. Conclusions: Distinct classes of adherence trajectories in pediatric IBD can be identified with longitudinal data collection approaches; however, disease and regimen factors offered limited value in predicting adherence trajectory class. Future research should utilize longitudinal conceptualizations of adherence and examine alternative predictors of declining adherence over time.