Healthcare Costs for Crohn's Disease Patients Treated with Infliximab: a Propensity Weighted Comparison of the Effects of Treatment Adherence

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.

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).

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.