We built a decision analytic model to evaluate the cost-utility of four commonly used treatment strategies: intravenous immunoglobulin G (IVIG) 0.8 g/kg, anti-D 75 mcg/kg, methylprednisolone (30 mg/kg for 3 days), and prednisone (4 mg/kg/day for 4 days). In our baseline model, all children were hospitalized upon presentation, and discharged once the platelet count reached > or =20,000. We performed a literature search to estimate time to platelet count > or =20,000 for each strategy, as well as the probability of side effects. We obtained cost data and quality of life measures from institutional and published data sources.
The clinical benefit of anti-D is offset by a substantial cost increase. Although often overlooked in favor of newer agents, a brief course of high-dose prednisone is an inexpensive and effective treatment for acute ITP.
The primary objective in the treatment of acute pediatric idiopathic thrombocytopenic purpura (ITP) is to rapidly increase the platelet count.
Total cost of one-time treatment for a 20 kg child was US dollars 786 with prednisone, US dollars 1,346 with methylprednisolone, US dollars 2,035 with anti-D, and US dollars 2,492 with IVIG. The strategies of IVIG and methylprednisolone were less effective and more expensive than anti-D and prednisone, respectively. Although anti-D caused the most rapid rise in platelet counts, the incremental cost-utility ratio (costs incurred by using anti-D instead of prednisone divided by health benefit of using anti-D instead of prednisone) was US dollars 7,616 per day of severe thrombocytopenia avoided, primarily due to the much higher medication cost of anti-D. Utilizing an outpatient model, the cost difference between anti-D and prednisone was even more striking.