Healthcare costs for Crohn's disease patients treated with infliximab: A propensity weighted comparison of the effects of treatment adherence

Abstract

Objective: The objective for the research was to evaluate the direct healthcare costs for Crohn's disease (CD) patients categorized by adherence status. Methods: Adult patients with ≥1 claim for infliximab and ≥2 claims for CD who were continuously insured for 12 months before and after their first infliximab infusion (index date) were identified in a 2006-2009 US managed care database. Patients were excluded if they had rheumatoid arthritis claims, received infliximab billed as a pharmacy benefit, or received another biologic drug. Patients were categorized as being either adherent or intermittently adherent to infliximab using a pre-defined algorithm. Total and component direct costs, CD-related costs, rates of surgery, and days of hospitalization were estimated for the 360-day post-index period. Propensity weighted generalized linear models were used to adjust the cost estimates for potential confounding variables. Conclusions:Greater drug-related costs for infliximab adherent patients were offset by lower costs from hospitalization and outpatient visits. These findings indicate that adherent patients have improved clinical outcomes, at a similar aggregate cost, than patients who are only intermittently adherent to therapy. Results: The total propensity weighted cost for infliximab adherent patients was 40,425 (95% CI=[38,686, 42,242]), compared to 41,082 (95% CI=[38,163, 44,223]) for the intermittently adherent (p=0.71). However, adherent patients had lower total direct medical costs, exclusive of infliximab, that were 13,097 (95% CI=[12,141, 14,127]) compared with 20,068 (95% CI=[17,676, 22,784]) for intermittently adherent patients as a result of substantially lower hospital and outpatient costs (p<0.0001).