Impact of infliximab adherence on Crohn’s disease-related healthcare utilization and inpatient costs

Abstract

Few published reports have described the impact of adherence with biologic agents on hospitalizations and inpatient costs in Crohn's disease (CD). A retrospective claims analysis using the IMS LifeLink Health Plan Claims Database between September 1, 2004 and June 30, 2009 was conducted. Continuous enrollment for 12 months before and 12 months after the index date was required. Patients were required to have ≥2 claims with an International Classification of Diseases, 9th Edition, Clinical Modification diagnosis code for CD (555.xx) preindex, be ≥18 years of age at index, and have ≥4 infliximab infusions with a gap no greater than 12 weeks between each infusion. Patients with 7-9 infliximab infusions (12 months postindex) were considered adherent; patients with 4-6 infliximab infusions were considered nonadherent. In total, 638 patients were included in the analyses (mean age, 43 years; 58% female in the adherent group and 53% in the nonadherent group). The number of patients who met the definition of adherence was 466 (73%). A smaller proportion of adherent patients had a CD-related emergency room visit, compared with nonadherent patients (11% vs. 17%, P=0.029). A smaller proportion of adherent patients required CD-related hospitalization, compared with nonadherent patients (8% vs. 12%, P=0.117). Among those hospitalized, adherent patients had fewer mean [median] days in the hospital (5.9 [5] days), compared with nonadherent patients (12.8 [8] days, P=0.015). Mean [median] hospital costs were significantly lower for adherent patients ($13,427 [$9,352]), compared with nonadherent patients ($37,783 [$28,864], P=0.001). Multivariate analyses confirmed lower inpatient (P<0.001) costs for adherent versus nonadherent patients. Adherence with infliximab therapy during the first year of treatment in patients with CD was associated with a shorter hospital length of stay and lower inpatient costs compared with nonadherent patients. Strategies for increasing adherence rates to infliximab maintenance therapy may be valuable in reducing hospitalizations and inpatient costs in patients with CD.