In 10% to 20% of cases, Kawasaki disease is refractory to intravenous immunoglobulin (IVIg), an expensive medication under a national shortage. Data suggest that infliximab is a viable alternative to a second dose of IVIg, with similar efficacy and safety. We compared the cost of a second IVIg dose to that of infliximab in the treatment of refractory Kawasaki disease (rKD).
A decision analysis model was used to compare rKD treatments: a second dose of IVIg at 2 g/kg versus infliximab at 10 mg/kg. Infliximab monitoring times were 24, 36, and 48 hours. Direct hospital costs beginning at rKD diagnosis were estimated by using 2016-2017 Truven MarketScan data. Redbook was used for drug costs. Calculations were applied to 3 hypothetical cohorts of 100 patients aged 2 (12.5 kg), 4 (16 kg), and 8 years (25.5 kg). Indirect costs included parental missed workdays.
The total direct cost for children receiving IVIg was $1 677 801, $1 791 652, and $2 100 675 for the 2-, 4-, and 8-year-old cohorts. The direct cost of infliximab with 24 hours of monitoring was $853 042, $899 096, and $1 024 101, respectively. A 20% bidirectional sensitivity analysis revealed stability of our model, with overall cost savings with use of infliximab. With monitoring 48 hours after infliximab treatment, 20% changes in length of stay (LOS) tipped the balance for the 2- and 4-year-old cohorts. Overall, IVIg and infliximab LOS had the most influence on our model.
Infliximab has potential to yield shorter LOS and significant cost savings in the treatment of rKD. Infliximab treatment, followed by 24 hours of monitoring, nearly halved hospital costs, regardless of age.