Adherence to infliximab maintenance therapy and health care utilization and costs by Crohn's disease patients.

INTRODUCTION: Studies suggest infliximab decreases hospitalization and surgery rates in Crohn'fs disease (CD). The aim of this analysis was to evaluate adherence to infliximab maintenance therapy and the impact of medication adherence on health care utilization and costs by patients with CD.
METHODS: Patients with CD who had at least four infliximab infusions (with the time between consecutive infusions < or =12 weeks for the first four infusions) during the first year following infliximab initiation (index date) were identified from the Integrated Health Care Information Service claims database (2002-2006). Nonadherence was defined as fewer than seven infliximab infusions in the first year. One-year health care resource utilization and costs (excluding infliximab drug and administration costs) were compared between adherent and nonadherent patients, with adjustment for baseline characteristics.
RESULTS: A total of 571 patients with CD who were receiving infliximab maintenance therapy were identified. The infusion-based nonadherence rate was 34.3% during the first year of therapy. The multivariate analysis demonstrated that compared with adherent patients, nonadherent patients were more likely to have been hospitalized (odds ratio [OR]=2.7 [all-cause] and OR=2.5 [CD-related]; both P<0.001). Compared with infliximab-adherent patients, adjusted medical costs by nonadherent patients were 73% ($6,692) and 90% ($4,961) greater for all-cause and CD-related medical costs, respectively (both P<0.001), and adjusted hospitalization costs were 115% ($11,450) and 115% ($9,570) greater for all-cause and CD-related hospitalization costs, respectively (both P<0.001).
CONCLUSION: More than one-third of patients on infliximab maintenance therapy were nonadherent to recommended maintenance. Further, nonadherence was associated with increased medical costs and a greater rate of hospitalization.