Cost-Effectiveness Analysis of Second Intravenous Immunoglobulin Infusion versus Infliximab for Treating IVIG-resistant Kawasaki Disease Patients

Objective Intravenous immunoglobulin (IVIG) is a known effective treatment to reduce the incidence of coronary artery aneurysms in Kawasaki disease (KD) patients. However, there has been an increase in IVIG-resistant patients and a lack of clinical trial data to determine the best second treatment. The Kawasaki Disease Comparative Effectiveness (KIDCARE) trial was a randomized trial comparing infliximab to a second IVIG infusion. Data from the trial were used for a cost-effectiveness analysis. Methods We developed a decision tree to estimate total costs and outcomes and calculated cost-effectiveness ratios for both treatment pathways. Cost and resource use was estimated from IBM MarketScan Commercial Database, US Bureau Labor of Statistics, IBM Micromedex Redbook and relevant peer-reviewed sources. Outcomes were measured using fever free days based on the KIDCARE study results. We addressed uncertainty using a one-way sensitivity analysis. Results Infliximab was the less costly treatment pathway in children with IVIG-resistant KD compared to a second dose of IVIG. The second IVIG treatment pathway cost $1,809 per additional fever free day while the infliximab treatment pathway cost $1,289 per additional fever free day. The incremental cost-effective ratio (ICER) was -$11,812 and was most sensitive to patient weight due to weight-based dosing but infliximab remained cost-effective. Conclusions Infliximab was the dominant economic treatment choice compared to a second dose of IVIG under a range of assumptions for both treatment patterns. This study suggests that clinicians could consider this when choosing treatment for IVIG-resistant KD patients.