Comparison of Ideal vs. Actual Body Weight Dosing of Intravenous Immunoglobulins for Immune Thrombocytopenia: A Retrospective Analysis

Introduction Intravenous immunoglobulin (IVIG) is a weight‐based therapy used to treat immune thrombocytopenia (ITP). Although pharmacokinetic data support the use of ideal body weight (IBW)–based dosing, clinical outcomes for this dosing strategy are lacking. Materials and Methods This retrospective, multicenter chart review was conducted across five institutions compared clinical outcomes and costs for patients with ITP treated with IVIG dosed via actual body weight (ABW) or IBW. Data were collected from November 1, 2019 to April 10, 2024. The primary outcome was early platelet response, and secondary outcomes included length of stay (LOS) and increase in platelet count. Results A total of 94 patients were included for analysis. No significant differences were noted between the ABW and IBW groups for early platelet response (59.1% vs. 47.2%, p = 0.466), LOS (9 vs. 6 days, p = 0.111), and the increase in platelet count (54.5 vs. 18.5 × 10 9 /L, p = 0.681). The estimated average cost of IVIG per patient was $5231.87 lower for the IBW group. Conclusions The utilization of IBW‐based dosing of IVIG for ITP treatment was not associated with a change in early platelet response, LOS, or increase in platelet count compared with ABW‐based dosing but was associated with cost savings.