ABSTRACT
AIMS: To compare long-term healthcare resource utilization (HCRU) and costs among patients who initiated ixekizumab (IXE) or adalimumab (ADA) for treatment of psoriasis in the United States. METHODS: Adult patients with psoriasis who had ≥1 claim for IXE or ADA were identified from IBM MarketScan claims databases prior to the COVID-19 pandemic (1 March 2016-31 October 2019). The index date was the date of first claim for the index drug of interest. Inverse probability of treatment weighting was employed to balance treatment cohorts. All-cause and psoriasis-related HCRU and costs were examined for 24 months of follow-up. Costs were reported as per patient per month. Costs of psoriasis-related biologics were adjusted using published Institute for Clinical and Economic Review (ICER) discount factors. Index drug costs were adjusted for adherence and ICER discount rates. RESULTS: The analyses included 407 IXE and 2,702 ADA users. IXE users had significantly higher inpatient admission rate (all-cause HCRU: 14.9% vs. 11.0%; p =0.012) and greater mean length of stay per admission (days, 6.6 vs. 4.1; p =0.004) than ADA users. ICER-adjusted costs were significantly higher in IXE than ADA users (all-cause costs: $4,132 vs. $3,610; p <0.001; psoriasis-related costs $3,077 vs. $2,700; p <0.001). After adjusting for ICER and adherence, IXE and ADA drug costs were comparable ($3,636 vs. $3,677; p =0.714). LIMITATIONS: Study relied on administrative claims data, subjected to data coding limitations and data entry errors. Rebates, patient assistance programs, and commission to wholesalers are not always captured in claims. Adjustment made by ICER discount factors may lead to double-discounting if the discounts have been applied in claim payments. CONCLUSIONS: All-cause HCRU was higher in IXE than ADA users. Healthcare costs were also higher in IXE than ADA users after ICER adjustment, over 24 months. Cost differences were largely driven by higher treatment adherence associated with IXE. Index drug costs were comparable after ICER and adherence adjustments.