Clinical Study

The Frequency Of Mismatch Between Hemoglobin A1c And Other Measures Of Glycemic Control In An Urban Academic General Medicine Clinic: The Role Of Fructosamine And Continuous Glucose Monitoring In Primary Care

Posted Date: Jul 13, 2021

  • Investigator: Jared Friedman
  • Specialties: Diabetes, Endocrinology
  • Type of Study: Observational/Survey

Hemoglobin A1c (HbA1c) has been used in clinical practice for decades for measuring patient glycemic control and risk of complications. While HbA1c has known testing limitations, specifically in patients with anemia or hemoglobinopathy, a growing body of work suggests that a discordance exists between hemoglobin A1c and alternative measures of glycemic control including fingerstick glucose readings, continuous glucose monitors, and extracellular serum protein glycation products such as fructosamine. This study has two primary aims:1) to determine the frequency of clinically significant mismatch between hemoglobin A1c and various alternative measures particularly in an urban, General Internal Medicine clinic and factors that may be associated and 2) confirm with more rigorous continuous glucose monitoring (CGM) that a true mismatch is present with HbA1c. This differs from prior work which has been focused on a standardized population within a specialized diabetes or endocrinology clinic and is structured to coordinate with existing clinic quality improvements focused on HbA1c based clinical decision making in the General Medical clinic. We plan to enroll 200 subjects; eligible participants will complete a demographic and diabetes history survey and will complete two blood draws separated by at least 90 days which will include a simultaneous hemoglobin A1c and fructosamine. For subjects found to have the largest “mismatch” between hemoglobin A1c and expected A1c derived from fructosamine, their glycemic control will be further analyzed with a fourteen-day usage of a CGM device to derive a Glucose Management Indicator (GMI) which is essentially a prediction of HbA1c based on fourteen days of continuous glucose data. We hypothesize that a frequency of at least 25% of the Internal Medicine clinic census has a mismatch of >1% between hemoglobin A1c and expected A1c from fructosamine. Furthermore, we expect that the GMI will further confirm mismatch compared to HbA1c in greater than 75% of the patients. We will use the information from the demographic survey and baseline lab data to identify characteristics of patients with the presence of mismatch whose glycemic control may be better evaluated with the addition of a surrogate measure such as fructosamine or CGM rather than solely hemoglobin A1c. In patients with known variability that is reproducible, we may be able to determine an “adjusted HbA1c” that can more reliably reflect risk of diabetes complications and guide treatment options. As one of the primary parameters of the quality of diabetes care in the General Medicine clinic is HbA1c, we believe that this study has the potential to improve quality of diabetes care while fostering clinical collaboration between the Division of General Internal Medicine and Endocrinology.




Diabetes, A1c, Fructosamine

For More Information:

Jared Friedman, Md

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