Purpose: The primary objective of this study was to evaluate the total potential grams of intravenous immune globulin (IVIG) averted using ideal body weight (IBW) versus actual body weight (ABW) for dosing calculations. The secondary objectives assessed the indication for use of IVIG, change in serum immunoglobulin G (IgG) levels, and potential cost savings of using IBW to dose IVIG as an alternative to ABW.
Background: Dosing of IVIG in clinical studies is based on ABW. Increasing evidence suggests it is more appropriate to dose IVIG using IBW in all patients, given it primarily distributes throughout intravascular and extravascular fluid compartments. Recent studies have demonstrated benefit for the use of IBW for IVIG dosing in regard to outcomes such as grams of drug averted, guideline compliance, and changes in serum IgG levels. This study aimed to add to the body of literature supporting use of IBW for dosing of IVIG.
Methods: A retrospective chart review was conducted for patients administered IVIG therapy between May 1, 2018 and November 30, 2018. IBW was calculated per patient using the Devine equation.
Data Anaysis : Descriptive statistics were used to assess all primary and secondary objectives. This included examining medians and interquartile ranges for the primary objective as well as potential cost savings per dose.
Results: In regard to the primary objective, the total potential grams of IVIG averted was 965 grams. In terms per dose, a median of 45 grams of IVIG per patient could have been averted, with a range from 0 to 75 grams. In regard to secondary objectives, the total potential cost savings was $41,038.57. In terms per dose, a median of $252.43 per patient could have been avoided, with a range from 0 to $634.51. IVIG was most commonly being prescribed for primary humoral immunodeficiency states and chronic lymphocytic leukemia.
Implications: This data may help guide the decision to transition to utilization of IBW for IVIG dosing. In addition, it may give further insight regarding the need to create a pharmacy-to-dose protocol for IVIG.
