Empirically Establishing Blood Glucose Targets to Achieve HbA1c Goals

  1. David M. Nathan1
  1. 1Diabetes Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA
  2. 2Biostatistics Center, Massachusetts General Hospital, Boston, MA
  1. Corresponding author: Nancy Wei, ncwei{at}partners.org.


OBJECTIVE To determine the average fasting, postprandial, and bedtime self-monitored blood glucose (SMBG) concentrations associated with specified HbA1c levels using data from the hemoglobin A1C-Derived Average Glucose (ADAG) study.

RESEARCH DESIGN AND METHODS The ADAG study was a multicenter observational study that used continuous glucose monitoring and SMBG testing to determine the relationship between mean average glucose and HbA1c. We used the SMBG data from 470 of the ADAG study participants (237 with type 1 diabetes and 147 with type 2 diabetes) to determine the average fasting, premeal, 90-min postmeal, and bedtime blood glucose (BG) for predefined target HbA1c groups between 5.5 and 8.5% (37–69 mmol/mol). t tests were used to compare mean BG values between type 1 and type 2 diabetes groups.

RESULTS The average fasting BG needed to achieve predefined HbA1c target levels of 5.5–6.49% (37–47 mmol/mol), 6.5–6.99% (48–52 mmol/mol), 7.0–7.49% (52–58 mmol/mol), 7.5–7.99% (58–64 mmol/mol), and 8.0–8.5% (64–69 mmol/mol) were 122 mg/dL with 95% CI 117–127, 142 mg/dL (135–150), 152 mg/dL (143–162), 167 mg/dL (157–177), and 178 mg/dL (164–192), respectively. Postmeal BG to achieve the HbA1c level of 6.5–6.99% (48–52 mmol/mol) and 7.0–7.49% (52–58 mmol/mol) were 139 mg/dL (134–144) and 152 mg/dL (147–157), respectively. Bedtime BG was 153 mg/dL (145–161) and 177 mg/dL (166–188), respectively.

CONCLUSIONS We have determined the average BG premeal, postmeal, and at bedtime to achieve a variety of HbA1c targets. These results, based on empirical data, will help patients and providers set realistic day-to-day SMBG targets to achieve individualized HbA1c goals.

  • Received September 13, 2013.
  • Accepted December 8, 2013.

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