Optimization of Dosing of Immunoglobulin G in the Obese Population

The estimated prevalence of overweight and obese individuals >20 years in the US is 154.7 million (nearly double since the early 1960s), and over 1.6 billion people are considered overweight or obese worldwide. Compounding the health risks associated with obesity is the insufficient data supporting dosing strategies for a variety of medication used to treat conditions encountered in obese patients. No consensus on the best dosing strategy for IgG in obese patients has been established. Total (TBW), ideal (IBW), and adjusted (AdjBW) body weight-based dosing are being utilized by different institutions. Thus, there is an urgent need to identify evidence supporting optimal dosing strategies for IgG.

It has been proposed that using TBW to dose IgG in obese patients may increase the risk of thrombosis owing to increased blood viscosity, activation of platelets, or vasospasm; and the increase in blood viscosity has been reported as IgG dose dependent. The use of using IBW or AdjBW has been advocated to reduce the side effect and drug expenditures. It is currently unknown what the clinical impact is of using measures of body weight other than TBW to calculate IgG doses, and the effect of obesity on IgG pharmacokinetics has not been experimentally evaluated.