Minimal Model-Derived Insulin Sensitivity Index Underestimates Insulin Sensitivity in Black Americans.

Objective: To examine the ethnic differences in insulin sensitivity (S) as measured by the minimal model approach (S-MM) and the reference method, the euglycemic-hyperinsulinemic clamp (EHC).

Research Design And Methods: In a prospective study design, thirty Black Americans (BA) were age, sex, and BMI matched with non-Hispanic Whites (NHW). Participants underwent frequently sampled intravenous tolerance test (FSIVGTT) and EHC on 2 separate days during a single visit.

Results: S-MM values were significantly lower in BA when compared with NHW (0.035 ± 0.025 vs. 0.058 ± 0.036 [dL/min]/[μU/mL]; = 0.003). However, there were no ethnic differences in S measured by EHC (0.028 ± 0.012 vs. 0.035 ± 0.019 [dL/min]/[μU/mL]; = 0.18).

Conclusions: S-MM systematically underestimates S in BA when compared with NHW. These findings suggest that studies inferring lower S in BA based on FSIVGTT and S-MM should be interpreted cautiously.