Optimization of intravenous immune globulin use at a comprehensive cancer center

Intravenous immune globulin (IVIG) is a high-cost medication used in a diverse range of settings. At many institutions, IVIG is dosed using total body weight (TBW). Recent evidence suggests that alternative dosing weights reduce waste without compromising clinical outcomes. The objective of this study was to quantify the waste reduction potential generated through the use of alternative IVIG dosing weights.

We performed a retrospective analysis of all IVIG doses administered from January 2011 through January 2016 to adults (≥18 years). TBW and height at the time of administration were used to calculate prescribed dose (g/kg), ideal body weight (IBW), and adjusted body weight (AdjBW). Three dosing methods were analyzed, as follows: use of AdjBW if TBW is >120% IBW (method 1), AdjBW for all doses (method 2), and IBW for all doses (method 3). Outcomes included potential IVIG use averted, direct drug cost savings, and reductions in outpatient infusion times for each method.

A total of 9,918 doses were administered to 2,564 patients over 5 years, representing an average usage of 75,994 g/year. If dosing methods 1, 2, and 3 had been used, the annual use of IVIG would have decreased by 21.9% (16,658 g/year, p < 0.001), 24.2% (18,371 g/year, p < 0.001), and 35.9% (27,252 g/year, p < 0.001), respectively. This translates into average annual cost differences of $2.37 million, $2.62 million, and $3.89 million and average annual outpatient infusion time savings of 841 hours, 920 hours, and 1,366 hours, respectively.

IVIG dosing optimization through use of alternative dosing weights represents a significant source of waste reduction and cost reduction.