HOMA2 - %B

In part 2 of the ODX HOMA2 Series we continue our exploration of the HOMA2 calculator by examining HOMA2-%B - an amazing way to gauge the beta cell output of insulin from the pancreas

HOMA2 - %B: An Index For Gauging the Beta Cell Output of Insulin from the Pancreas

Dicken Weatherby, N.D. and Beth Ellen DiLuglio, MS, RDN, LDN

The ODX HOMA2 Series

1. HOMA2 part 1 - The HOMA2 Calculator: An Important Series of Indices for Gauging Insulin Resistance
2. HOMA2 part 2 - HOMA2 - %B: An Index For Gauging the Beta Cell Output of Insulin from the Pancreas
3. HOMA2 part 3 - HOMA2 - %S: An Index For Assessing Cellular Sensitivity to Insulin
4. HOMA2 part 4 - HOMA2 - IR: An Index For Assessing the Degree of Insulin Resistance
5. Bonus - QUICKI – An Additional Index for Assessing Insulin Resistance in Our Patients
6. Optimal - The Podcast: Episode 5: The HOMA2 Calculator in Clinical Practice - an Interview with Dr. Brad Rachman

The beta cells of the pancreatic islets are responsible for production and secretion of insulin. Beta cells have a small capacity to store insulin, and the stored insulin is secreted immediately upon elevation of blood glucose levels, causing a resultant short-term increase in blood insulin levels.

Reduced insulin release in this initial phase is the earliest known detectable indicator of beta cell dysfunction, and is an independent predictor of Type 2 Diabetes.

Traditionally, the Oral Glucose Tolerance Test is used to assess for diabetes, insulin resistance, and impaired beta cell function, however it does not have the capacity to distinguish between peripheral insulin resistance and a reduced capacity of the pancreatic beta-cell to produce insulin. The HOMA2 (Homeostasis Model Assessment) calculator can therefore be used to provide a more detailed picture of physiologic changes, and treatment can be directed accordingly. 

The HOMA2 calculator is a tool used to express the degree of insulin sensitivity and insulin resistance in the patient from the following biomarkers: Fasting Blood Glucose, Fasting Insulin and/or C-Peptide. 

The secretory capacity of the pancreatic islet beta cells is expressed by the HOMA2 calculator as HOMA2-%B, where the higher the value, the more insulin the beta cells have to secrete to respond to blood glucose levels. 

Evidently, the HOMA2-%B measure is directly linked to the level of insulin resistance in the patient, as expressed by the HOMA2-IR measurement, and as such, assessment of HOMA2-%B without also assessing HOMA2-IR will not give a complete picture of metabolic state. 

Is there a normal range for HOMA2 values?

According to the Diabetes Trials Unit, the creators of the HOMA2 calculator "There is no absolute value for HOMA indices. These will depend on the specific assays used for glucose, insulin and C-peptide. Because of this, there are no defined thresholds for ‘normal’ vs. ‘abnormal’ values. Please see the following document for further details." 

That being said, there is evidence that there is evidence that a normal-weight, healthy person younger than 35 years old with no insulin resistance and normal functioning beta cells will have a HOMA2-%B measurement of 100.

Implications of high HOMA2-%B levels focusing on the "dysfunctions" as much as the pathology

In the initial stages of insulin resistance, where an increasing level of insulin is required to respond to blood glucose levels, HOMA2-%B measurement will INCREASE, representing the increased activity of the beta cells, and the increased insulin being secreted. 

Elevated HOMA2-%B measurements in addition to elevated HOMA2-IR measurements is indicative of pre-diabetes, and dietary and lifestyle intervention should be initiated. 

Implications of low HOMA2-%B levels focusing on the "dysfunctions" as much as the pathology 

After prolonged, untreated insulin resistance and overactivity of beta cells, the beta cells will lose their capacity to maintain an increased activity level, beta cell function and insulin production will decline, and this will be expressed by a DECREASE in the HOMA2-%B measurement. 

A decreasing HOMA2-%B measurement (decline of beta cell function and insulin secretion), in addition to an elevated HOMA2-IR measurement (rising level of insulin resistance) is indicative of progression to Type 2 Diabetes Mellitus. 

Is HOMA2-%B included in the Optimal DX software?

Yes! Optimal DX now gives our users the ability to add the 3 HOMA2 calculations to their patient’s Functional Health Reports.

Up Next - HOMA2 - %S: An Index For Assessing Cellular Sensitivity to Insulin

Research

Song, Young Seok et al. “Comparison of the Usefulness of the Updated Homeostasis Model Assessment (HOMA2) with the Original HOMA1 in the Prediction of Type 2 Diabetes Mellitus in Koreans.” Diabetes & metabolism journal vol. 40,4 (2016): 318-25.

Wallace, Tara M et al. “Use and abuse of HOMA modeling.” Diabetes care vol. 27,6 (2004): 1487-95.

Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28(7):412-9.

Caumo, Andrea et al. “New insights on the simultaneous assessment of insulin sensitivity and beta-cell function with the HOMA2 method.” Diabetes care vol. 29,12 (2006): 2733-4.

Levy JC, Matthews DR, Hermans MP. Correct homeostasis model assessment (HOMA) evaluation uses the computer program. Diabetes Care. 1998;21(12):2191-2.

Susan E. Manley, Irene M. Stratton, Penelope M. Clark, and Stephen D. Luzio. Comparison of 11 Human Insulin Assays: Implications for Clinical Investigation and Research. Clinical Chemistry 2007;53:5 922–932.

Interpretation of HOMA Indices https://www.dtu.ox.ac.uk/homacalculator/HOMANoNormalRange.pdf