Risk factors for non-adherence to disease-modifying therapy in pediatric multiple sclerosis

Background: Adherence to disease-modifying therapies (DMTs) in pediatric multiple sclerosis (MS) is not well understood. We examined the prevalence and risk factors for poor adherence in pediatric MS. Methods: This cross-sectional study recruited youth with MS from 12 North American pediatric MS clinics. In addition to pharmacy-refill data, patients and parents completed self-report measures of adherence and quality of life. Additionally, patients completed measures of self-efficacy and well-being. Factor analysis and linear regression methods were used. Results: A total of 66 youth (mean age, 15.7 years) received MS DMTs (33% oral, 66% injectable). Estimates of poor adherence (i.e. missing >20% of doses) varied by source: pharmacy 7%, parent 14%, and patient 41%. Factor analysis yielded two composites: adherence summary and parental involvement in adherence. Regressions revealed that patients with better self-reported physical functioning were more adherent. Parents were more likely to be involved in adherence when their child had worse parent-reported PedsQL School Functioning and lower MS Self-Efficacy Control. Oral DMTs were associated with lesser parental involvement in adherence. Conclusion: Rates of non-adherence varied by information source. Better self-reported physical functioning was the strongest predictor of adherence. Parental involvement in adherence was associated with worse PedsQL School Functioning and lower MS Self-Efficacy-measured confidence in controlling MS.