Adherence to the Outpatient Oral Medication Regime in Adolescent HSCT Recipients

Introduction: Hematopoietic stem cell transplantation (HSCT) is an increasingly utilized treatment option for adolescents with a wide range of life-threatening diagnoses. Following discharge, adolescents who have undergone HSCT must manage a complex treatment regimen including numerous oral and/or intravenous medications. Suboptimal adherence to this medication regimen may result in sub-therapeutic medication exposure, potentially compromising treatment effectiveness and, subsequently, increasing the risk of adverse medical outcomes. During adolescence, individuals are increasingly likely to experience stressors (e.g., increased conflict with caregivers) linked to decreased adherence. As such, it is important to understand adherence in this potentially at-risk group. This study is the first to describe patterns of adherence in adolescents who have undergone HSCT.

Method: Data for this study are from a larger project examining adherence in pediatric HSCT recipients. Participants included eight adolescents (ages 12-18) who had undergone HSCT and their caregivers. Participants used Medical Event Monitors (MEMS™), electronic pill bottles that report time-stamped indications of bottle openings to track adherence for the duration of the study (9 mo.), until all oral medications were discontinued (n = 2), or until the device was lost/no longer provided for download (n = 2), resulting in an average of 195.63 monitored days (SD = 119.87 days). Daily adherence was calculated by dividing the number of recorded MEMS™ openings per day by the number of prescribed doses for that day. The average length of medication interruptions (≥ 24 hours between doses) was calculated for participants prescribed daily medication (n = 7). Caregivers provided demographics. Clinical characteristics were obtained via chart review.

Results: Participants were primarily male (63%), Caucasian (75%), and non-Hispanic (75%). On average, participants were 14.07 years of age (SD = 1.41 years) and received their transplant at 14.00 years of age (SD = 1.41 years). Adherence data are presented in Table 1. Participant level data will also be presented.

Table 1
	M (SD)	Range
Percentage of prescribed doses taken	70.39 (21.47)	28.21 – 92.50
Percentage of days with correct number of doses taken	55.43 (23.11)	20.51 – 88.18
Percentage of days with partial adherence (1 - 99%)	26.75 (17.18)	8.18 – 56.82
Percentage of days with no prescribed doses taken	17.81 (22.59)	0 – 64.10
Length of medication interruptions (≥ 24 hours between doses), days	4.46 (7.45)	0 – 36

Discussion: Overall, participants struggled to adhere to medication schedules, taking 70% of prescribed doses and demonstrating perfect adherence on fewer than four out of seven days per week. Adherence rates are similar to those observed in other pediatric populations and demonstrate the importance of routinely assessing adherence in adolescents who have undergone HSCT.