Nonadherence with thiopurine immunomodulator and mesalamine medications in children with Crohn disease

OBJECTIVES: To assess the prevalence of adherence to prescribed medications in children with Crohn disease and to identify possible factors associated with nonadherence. PATIENTS AND METHODS: This was a cross-sectional study of 51 pediatric patients with Crohn disease who were prescribed maintenance therapy with a thiopurine immunomodulator (6-mercaptopurine or azathioprine) and/or mesalamine during a 180-day period. Medication adherence rates were calculated from a validated formula using pharmacy records, and nonadherence was defined as a refill rate of <80% of the prescribed medication. Seventy-five percent of patients were prescribed thiopurine immunomodulators and 86% were prescribed mesalamine. RESULTS: The prevalence of nonadherence was 50% for the thiopurine immunomodulators and 66% for mesalamine. The mean number of emergency department visits for patients adherent to mesalamine was significantly greater than the nonadherent group (P < 0.0008). Having an emergency department visit increased the chances of a patient being adherent to mesalamine therapy by >9-fold (odds ratio, 9.6; 95% confidence interval, 1.87-52.17). The mean number of total health care visits was significantly greater for patients adherent to mesalamine (6.1 ± 0.8) compared with those who were not adherent (3.0 ± 0.4) (P < 0.001). CONCLUSIONS: These findings suggest that nonadherence to thiopurine immunomodulator or mesalamine therapy in pediatric patients with Crohn disease is common. Having a health care visit was associated with being adherent.