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

Beta cells in the pancreatic islets produce and secrete insulin. Beta cells have a limited capacity to store insulin, and they secrete stored insulin immediately when blood glucose rises, causing a 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 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 cannot distinguish between peripheral insulin resistance and reduced pancreatic beta-cell capacity to produce insulin. The HOMA2 (Homeostasis Model Assessment) calculator can therefore provide a more detailed picture of physiologic changes, and treatment can be directed accordingly. 

The HOMA2 calculator assesses insulin sensitivity and insulin resistance using the following biomarkers: Fasting Blood Glucose, Fasting Insulin, and/or C-peptide. 

The HOMA2 calculator expresses the secretory capacity of pancreatic islet beta cells as HOMA2-%B, where a higher value indicates that beta cells must secrete more insulin to respond to blood glucose levels. 

Evidently, HOMA2-%B is directly linked to insulin resistance, as measured by HOMA2-IR; therefore, assessing HOMA2-%B without also assessing HOMA2-IR will not provide 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 said, evidence suggests 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, when higher insulin is required to respond to blood glucose levels, HOMA2-%B will INCREASE, reflecting increased beta-cell activity and increased insulin secretion. 

Elevated HOMA2-%B measurements, along with elevated HOMA2-IR measurements, indicate prediabetes, 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 beta-cell overactivity, beta cells lose their capacity to maintain increased activity; beta-cell function and insulin production decline, which is reflected 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 lets users add the 3 HOMA2 calculations to their patients’ Functional Health Reports.

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

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