Is Intravenous Immunoglobulin (IVIG) dosed based on lean body mass or total body weight?

From the Guidelines

Intravenous Immunoglobulin (IVIG) is typically dosed based on total body weight rather than lean body mass, with a standard dosing range of 0.4-2 g/kg of total body weight, depending on the specific indication being treated. The most recent and highest quality study, 1, published in 2021, recommends high-dose IVIG (typically 2 gm/kg, based on ideal body weight) for the treatment of multisystem inflammatory syndrome in children (MIS-C). This study suggests that IVIG should be given to MIS-C patients who are hospitalized and/or fulfill Kawasaki disease criteria, with cardiac function and fluid status assessed before IVIG treatment is provided.

When considering the dosing of IVIG, it is essential to note that the volume of distribution for immunoglobulins includes both lean tissues and adipose tissue to some extent, making total body weight the more appropriate dosing parameter for most patients. However, some clinicians may consider adjusted body weight calculations to avoid excessive dosing in significantly obese patients (BMI >30), although this is not universally practiced.

The rationale for using total body weight is supported by the fact that immunoglobulins distribute throughout the extracellular fluid and plasma, which correlate better with total body weight than lean mass. Additionally, studies such as 1 and 1 have demonstrated the efficacy of IVIG in treating various conditions, including Kawasaki disease, with dosing based on total body weight.

In summary, the current evidence supports the use of total body weight for dosing IVIG, with a standard range of 0.4-2 g/kg, depending on the specific indication being treated. This approach is supported by recent and high-quality studies, including 1, which provides guidance on the treatment of MIS-C with IVIG.

Key points to consider when dosing IVIG include:

• Total body weight is the preferred dosing parameter
• Standard dosing range: 0.4-2 g/kg of total body weight
• Adjusted body weight calculations may be considered for significantly obese patients (BMI >30)
• Cardiac function and fluid status should be assessed before IVIG treatment is provided
• IVIG should be given to MIS-C patients who are hospitalized and/or fulfill Kawasaki disease criteria.

From the Research

Intravenous Immunoglobulin (IVIG) Dosing

• IVIG dosing can be based on either total body weight or lean body mass, with some studies suggesting that dosing based on adjusted body weight or ideal body weight may be more appropriate in certain cases 2, 3, 4, 5.
• The American Heart Association recommends a single infusion of 2 g/kg of IVIG for the treatment of Kawasaki disease, with the dose preferably given during the first 10 days of illness 6.
• Some studies have found that using adjusted body weight or ideal body weight for IVIG dosing can reduce waste and costs without compromising clinical outcomes 2, 3, 4, 5.
• A study found that using a precision-dosing strategy based on ideal body weight or adjusted body weight achieved $2600/month in institutional savings, with the opportunity for an additional $4600/month in savings with complete adherence to this dosing strategy 4.
• Another study found that optimizing IVIG use through alternative dosing weights could result in significant waste reduction and cost reduction, with potential annual cost differences of $2.37 million, $2.62 million, and $3.89 million 5.

Dosing Strategies

• Different dosing strategies for IVIG have been compared, including traditional dosing based on actual body weight, and precision dosing based on ideal body weight or adjusted body weight 2, 3, 4, 5.
• A study compared the effectiveness of using a precision-dosing strategy with a traditional-dosing strategy for IVIG in patients with hematologic malignancies, and found no difference in infection rate or IgG-level response between the two groups 4.
• Another study found that using alternative dosing weights, such as adjusted body weight or ideal body weight, could reduce IVIG use and costs without compromising clinical outcomes 5.

Clinical Outcomes

• Clinical outcomes associated with IVIG dosing based on ideal body weight or adjusted body weight have been studied, with some studies finding no difference in infection rate or IgG-level response compared to traditional dosing based on actual body weight 2, 3, 4.
• A study found that the implementation of a standardized ideal body weight IVIG dosing strategy was not associated with a statistically significant increase in 30-day hospital readmission or length of stay, but was associated with significantly fewer grams per dose given 3.
• Another study found that optimizing IVIG use through alternative dosing weights could result in significant waste reduction and cost reduction, without compromising clinical outcomes 5.