Rationale and Design for a GRADE Substudy of Continuous Glucose Monitoring

Diabetes Technol Ther. 2019 Dec;21(12):682-690. doi: 10.1089/dia.2019.0202. Epub 2019 Sep 4.

Abstract

Background: The Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) study has enrolled a racially and ethnically diverse population with type 2 diabetes, performed extensive phenotyping, and randomly assigned the participants to one of four second-line diabetes medications. The continuous glucose monitoring (CGM) substudy has been added to determine whether there are racial/ethnic differences in the relationship between average glucose (AG) and hemoglobin A1c (HbA1c). CGM will also be used to compare time in target range, glucose variability, and the frequency and duration of hypoglycemia across study groups. Methods: The observational CGM substudy will enroll up to 1800 of the 5047 GRADE study participants from the four treatment groups, including as many as 450 participants from each of 4 racial/ethnic minority groups to be compared: Hispanic White, non-Hispanic White, non-Hispanic African American, and non-Hispanic Other. CGM will be performed for 2 weeks in proximity to a GRADE annual visit, during which an oral glucose tolerance test will be performed and HbA1c and glycated albumin measured. Indicators of interindividual variation in red blood cell turnover, based on specialized erythrocyte measurements, will also be measured to explore the potential causes of interindividual HbA1c variations. Conclusions: The GRADE CGM substudy will provide new insights into whether differences exist in the relationship between HbA1c and AG among different racial/ethnic groups and whether glycemic profiles differ among frequently used diabetes medications and their potential clinical implications. Understanding such differences is important for clinical care and adjustment of diabetes medications in patients of different races or ethnicities.

Keywords: Average glucose; Continuous glucose monitoring; Glycated hemoglobin; Interracial differences; Type 2 diabetes.

Publication types

  • Clinical Trial Protocol
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Black or African American
  • Blood Glucose / analysis
  • Blood Glucose Self-Monitoring
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Glycated Hemoglobin / analysis
  • Hispanic or Latino
  • Humans
  • Hypoglycemic Agents / therapeutic use*
  • Randomized Controlled Trials as Topic*
  • Research Design
  • White People

Substances

  • Blood Glucose
  • Glycated Hemoglobin A
  • Hypoglycemic Agents
  • hemoglobin A1c protein, human