Non-Adherence and Disease Severity in Pediatric Inflammatory Bowel Disease

Abstract

BACKGROUND: The treatment of Inflammatory Bowel Disease (IBD) involves complex medical and nutritional therapies that pose significant challenges to effective disease management (i.e., adherence to treatment regimens) for children and their families. Research on adherence rates in pediatric IBD has been largely descriptive, neglecting the relationship between adherence and disease symptoms and severity. The purpose of this study is to examine the relationship between medication non-adherence (i.e., aminosalicylates and thiopurine immunomodulators) and disease severity and symptoms in pediatric patients with IBD. METHODS: This study is part of a larger, ongoing, retrospective longitudinal observational cohort study of pediatric patients with a confirmed diagnosis of Crohn's disease, ulcerative colitis, or indeterminate colitis who were prescribed aminosalicylates and/or thiopurine immunomodulators and received a Physician Global Assessment (PGA) during regular clinic visits over a contiguous 2-year period. Fifty-three (53) pharmacy refill records with a prescription duration range of 364-803 days were obtained. Medication adherence rates were calculated based on the validated medication possession ratio formula. Physicians provided an assessment of IBD patients' disease severity using the PGA as part of standard clinic procedure for IBD patients. Chi-square analysis was performed to assess the association between adherence and disease severity. RESULTS: Thirty-one (31) patients were on an aminosalicylate, and 22 were on a thiopurine immunomodulator. Forty-three percent (43%) of all records obtained were identified as non-adherent, using an 80% cut point for medication refills. The rate of adherence for both medications was 78%. The prevalence of non-adherence to aminosalicylates and thiopurine immunomodulators was 50% and 30%, respectively. Patients taking aminosalicylates who were adherent were more likely to have quiescent disease severity than non-adherent patients (P = 0.0126). Similarly, adherent patients on thiopurine immunomodulators were also more likely to be quiescent (P = 0.0035). When the definition of non-adherence was defined as refilling less than 85% of prescribed medication, a stricter criterion, both groups showed quiescent disease severity with improved adherence (aminosalicylates P = 0.012; thiopurines P = 0.0113). CONCLUSION(S): These results suggest that disease severity is significantly related to poor medication adherence. This study should assist clinicians caring for pediatric patients with IBD by better understanding the impact of non-adherence on disease severity and ultimately inform the timing of early interventions aimed at improving adherence and quality of care in this population. This may also have implications for cost of delivered care as more adherent patients may require fewer hospitalizations and acute care visits, decreased surgical interventions, and perhaps a reduced need for step up therapy to more expensive medications (e.g., biologics).