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.