RESUMEN
OBJECTIVES: To assess the incidence and economic implications of loss of treatment response among patients with Crohn's disease (CD) treated with infliximab maintenance therapy. METHODS: This was a retrospective observational study of infliximab response and costs among patients with CD using a large health-care claims database. Patients with CD receiving infliximab maintenance therapy with an initial response were selected from the Integrated Healthcare Information Services claims database (1999-2005). Patients' claim histories were used to identify patterns of response to infliximab treatment. Incidence of loss of response was estimated using Kaplan-Meier method. Annual total health-care and CD-related costs were estimated and adjusted for inflation to 2005 US dollars. Generalized linear model was used to assess the impact of loss of response on treatment costs. RESULTS: The study sample included 262 patients with CD with an initial response to infliximab therapy. Within 24 months of therapy initiation, 77% of patients lost treatment response. Upward dose adjustment, a new drug therapy for CD, and CD-related emergency room or inpatient visits were the three most common indicators of loss of response. Both annual total and CD-related health-care costs for patients who lost treatment response during the first year were found to be approximately one-third higher than for those who did not lose response. CONCLUSIONS: The majority of patients who had initial responses to infliximab maintenance treatment subsequently lost response within 2 years. Loss of response was associated with a significant increase in total health-care and CD-related costs.