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Association of Baseline Characteristics With Insulin Sensitivity and β-Cell Function in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) Study Cohort

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posted on 17.12.2020, 18:15 by Neda Rasouli, Naji Younes, Kristina M. Utzschneider, Silvio E. Inzucchi, Ashok Balasubramanyam, Andrea L. Cherrington, Faramarz Ismail-Beigi, Robert M. Cohen, Darin E. Olson, Ralph A. DeFronzo, William H. Herman, John M. Lachin, Steven E. Kahn, the GRADE Research Group
Objective: We investigated sex and racial differences in insulin sensitivity, β-cell function and HbA1c, and the associations with selected phenotypic characteristics.

Research Design and Methods: This is a cross-sectional analysis of baseline data from 3,108 GRADE participants. All had type 2 diabetes diagnosed <10 years and were on metformin monotherapy. Insulin sensitivity and β-cell function were evaluated using the homeostasis model assessment of insulin sensitivity (HOMA2-S) and estimates from oral glucose tolerance tests including the Matsuda index, insulinogenic index (IGI), C-peptide index (CPI) and oral disposition index (DI).

Results: The cohort was 56.6±10 years of age (mean±SD), 63.8% male, with BMI 34.2±6.7 kg/m2, HbA1c 7.5±0.5% and type 2 diabetes duration 4.0±2.8 years. Women had higher DI than men but similar insulin sensitivity. DI was the highest in Black/African Americans, followed by American Indians/Alaska Natives, Asians and Whites in descending order. Compared to white, American Indian/Alaska Native had significantly higher HbA1c but Black/African Americans and Asians had lower HbA1c. However, when adjusted for glucose levels, Black/African Americans had higher HbA1c than whites. Insulin sensitivity correlated inversely with BMI, waist to hip ratio, triglyceride to HDL cholesterol ratio (TG/HDL- C) and the presence of metabolic syndrome; whereas DI was associated directly with age and inversely with BMI, HbA1c and TG/HDL-C.

Conclusion: In the GRADE cohort, β-cell function differed by sex and race and was associated with the concurrent level of HbA1c. HbA1c also differed among the races, but not sex. Age, BMI and TG/HDL-C were associated with multiple measures of β-cell function and insulin sensitivity.


The GRADE Study is supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health under Award Number U01-DK-098246. The planning of GRADE was supported by a U34 planning grant from the NIDDK (U34-DK-088043). The American Diabetes Association supported the initial planning meeting for the U34 proposal. The National Heart, Lung, and Blood Institute and the Centers for Disease Control and Prevention also provided funding support. The Department of Veterans Affairs provided resources and facilities. Additional support was provided by grant numbers P30 DK017047, P30 DK020541-44, P30 DK020572, P30 DK072476, P30 DK079626, P30 DK092926, U54 GM104940, UL1 TR000439, UL1 TR000445, UL1 TR001108, UL1 TR001409, UL1 TR001449, UL1 TR002243, UL1 TR002345, UL1 TR002378, UL1 TR002489, UL1 TR002489, UL1 TR002529, UL1 TR002535, UL1 TR002537, and UL1 TR002548. Educational materials have been provided by the National Diabetes Education Program. Material support in the form of donated medications and supplies has been provided by Becton, Dickinson and Company, Bristol-Myers Squibb, Merck, NovoNordisk, Roche Diagnostics, and Sanofi. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.