When MINMOD Artifactually Interprets Strong Insulin Secretion as Weak Insulin Action

Area of Science:

• Metabolic research
• Physiological modeling
• Clinical diagnostics

Background:

• The Bergman-Cobelli Minimal Model is widely used to estimate insulin sensitivity (S_i) from intravenous glucose tolerance tests (IVGTTs).
• Racial disparities in type 2 diabetes (T2D) risk are observed, with Black populations showing higher incidence.
• Previous studies using the Minimal Model suggested lower S_i in Black compared to White individuals, potentially explaining T2D risk differences.

Purpose of the Study:

• To identify limitations of the Bergman-Cobelli Minimal Model in estimating insulin sensitivity (S_i) during IVGTTs.
• To investigate potential reasons for observed racial differences in S_i estimates between Black and White populations.

Main Methods:

• Simulated IVGTT data were analyzed to assess the Minimal Model's performance under specific physiological conditions.
• Comparison of Minimal Model-derived S_i estimates with established methods like the hyperinsulinemic euglycemic clamp (HIEC).

Main Results:

• Simulated IVGTTs demonstrated that the Minimal Model can inaccurately estimate S_i, particularly when high Acute Insulin Response (AIR) is present.
• This inaccuracy may lead to the erroneous conclusion of lower S_i in certain populations, such as Black individuals, even when actual insulin sensitivity is normal.
• The rapid initial glucose rise and insulin dynamics in IVGTTs can be misinterpreted by the Minimal Model as reduced insulin sensitivity.

Conclusions:

• Caution is advised when interpreting Minimal Model-derived S_i estimates from IVGTTs, especially in diverse populations.
• The model's limitations may contribute to perceived racial differences in insulin sensitivity, potentially misattributing T2D risk.
• Further validation of the Minimal Model is needed, particularly concerning its application in studies comparing insulin sensitivity across different racial groups.