Clinical Cutoffs for Adherence Barriers in Solid Organ Transplant Recipients: How Many Is Too Many?

All correspondence concerning this article should be addressed to Cyd K. Eaton, MS, Department ofPsychology, University of Georgia, Athens, GA 30602. E-mail: cydeaton@uga.eduReceived July 21, 2014; revisions received October 24, 2014; accepted October 30, 2014Objective The current study used multiple statistical methods to determine empirically derived and clini-cally relevant cutoff scores on the Adolescent Medication Barriers Scale (AMBS) and Parent MedicationBarriers Scale (PMBS) to detect adolescents and young adults with solid organ transplants who experiencedmedication nonadherence or negative medical outcomes. Methods Participants included 71 patients and80 caregivers. Cutoff scores were determined via receiver operating characteristic curve analyses, t-test analy-ses, and the sensitivity and specificity of using certain cutoff scores. Results AMBS scores of 3 barriersand PMBS scores of 2 barriers were determined as the ideal cutoffs for identifying patients meeting criteriafor the outcome variables. Conclusions Clinicians should consider using these recommended cutoffscores when assessing adherence barriers in adolescents and young adults with solid organ transplants andtheir families. Patients or caregivers endorsing barriers above the cutoffs may benefit from further assessmentor intervention to address barriers, nonadherence, or related medical issues.Key words adherence; barriers; pediatric; transplant.Long-term survival rates after transplantation have im-proved considerably in the past decade, with 80% of pedi-atric recipients reaching adolescence and young adulthood(LaRosa, Baluarte, & Meyers, 2011). Receiving a transplanttrades a life-threatening illness for a chronic medical con-dition, requiring daily sustained adherence to medications(Griffin & Elkin, 2001; LaRosa et al., 2011). Medicationregimens after transplantation are complex, requiring alarge number of different medications to be administeredusing schedules that change frequently (Shellmer, Dabbs,& Dew, 2011). In pediatric chronic illness populations,rates of medication adherence are approximately 50% (LaGreca & Mackey, 2009). In adolescents and young adults(AYAs), a recent systematic review of the literature indi-cated that, on average, 43% of patients are nonadherentto their immunosuppressant medications (Dobbels et al.,2010). Adolescence and young adulthood represent timesof transition into more responsible and autonomous rolesacross all domains of life. This transition creates opportu-nities for missteps, resulting in higher rates ofnonadherence in this age-group and organ rejection ratesthat are second only to individuals over the age of 65 years(La Greca & Mackey, 2009; Smith, Ho, & McDonald,2002).Medication nonadherence is the leading cause of organrejection (Shaw, Palmer, Blasey, & Sarwal, 2003), suggest-ing that the identification of factors influencing its occur-rence is critical. Late dosing is a form of medicationnonadherence that is particularly relevant to most antire-jection medications (e.g., tacrolimus, cyclosporine), giventhe need to maintain consistent therapeutic serum immu-nosuppressant blood levels to prevent organ rejection(Shemesh et al., 2004; Zelikovsky & Schast, 2008). Latedosing for non-antirejection medications additionally sug-gests that patients have difficulty establishing and followingroutines related to the medication regimen, in general, and