Diabetes Standards of Care and Resources for Clinicians and Educators

The A1C is one of the primary tests used to assess glycemic control. It should be measured in all patients with diabetes at the initial assessment and routinely as part of the continuing care.

Assessing A1C

• Measure A1C as frequently as every 3 months to monitor progress toward clinical targets and to facilitate therapeutic decision making.
• Measure A1C at least every 6 months for patients at goal.

A1C and Estimated Average Glucose (eAG)

Since A1C is expressed as a percentage, it can be difficult for some patients to understand how to relate their A1C result to blood glucose levels. Because eAG uses the same units (mg/dL) as home blood glucose measurements, the eAG may be easier to understand than the A1C and more useful when discussing patients' glucose goals and results.

The table below from the American Diabetes Association (ADA) shows the correlation of A1C and eAG. The ADA also provides a calculator for converting A1C results into eAG Exit Disclaimer: You Are Leaving www.ihs.gov  using the formula 28.7 X A1C – 46.7 = eAG.

Home blood glucose monitoring is an important and widely available tool that can be used to provide information needed to safely and effectively manage diabetes. It can help patients engage in self-care and manage glucose-lowering medications.

Self-Monitoring of Blood Glucose (SMBG)

• Recommend SMBG in patients when:
  • Taking insulin and/or multiple glucose-lowering medications
  • Medication therapy is initiated or changed
  • Hypoglycemia is a concern, especially when patients experience hypoglycemia unawareness
  • Risk of hyperglycemic crisis is a concern, such as diabetic ketoacidosis (DKA)
• Advise insulin-treated patients to perform SMBG ≥3 times a day if on multiple daily insulin injections or an insulin pump (alternatively consider Continuous Glucose Monitoring).

Continuous Glucose Monitoring (CGM)

CGM can provide valuable information on glucose patterns and glycemic control for patients and providers. It is particularly useful for identifying real-time glucose trends that may lead to hypoglycemia and hyperglycemia.

• Consider CGM for patients who are:
  • Identifying patterns of hypoglycemia
  • Experiencing severe hypoglycemia or hypoglycemia unawareness
  • Experiencing wide fluctuations in blood sugar
  • Using multiple daily insulin injections or an insulin pump
  • Pregnant and using insulin

Optimizing Glucose Monitoring in Clinical Care

• Identify potential barriers to monitoring, such as time constraints, fear, inconvenience, physical limitations, and cultural issues; assist in problem solving.
• Work collaboratively with patients on a monitoring plan. Provide guidance on how to use results in managing:
  • Meal plans
  • Medications
  • Physical activity level or other lifestyle changes
  • Sick days
• Review monitoring data and A1C results with the patient at each diabetes visit; utilize this information to optimize the management plan through shared decision making.

Using ranges in setting glycemic goals allows for the flexibility needed for patient safety and accounts for the limitations of testing accuracy. The Division of Diabetes Treatment and Prevention has developed a Glucose Management in Type 2 Diabetes Algorithm [PDF – 180 KB] which uses target ranges to provide guidance for individualizing clinical goals.

General Glycemic Control Goals

• A1C goal is <7% for most patients
• Self-monitoring of blood glucose (SMBG) targets:
  • Fasting and premeal: 80 to 130 mg/dL
  • Postmeal: <180 mg/dL measured 1-2 hours after the start of a meal
• Continuous glucose monitoring (CGM) target:
  • Time in range: 70% of values between 70 to 180 mg/dL (which correlates with an A1C of 7%)

Consider:

• More stringent goal if it can be achieved safely and without significant hypoglycemia or other adverse effects
• Less stringent goal for individuals with significant complications (e.g. cardiovascular disease, chronic kidney disease), advanced age, episodes of severe hypoglycemia, and/or comorbidities.

Individualizing Glycemic Targets

Treatment plans for achieving targets must be individualized for each patient. Discuss treatment goals with patients and agree on a specific individualized target range of glycemic control after reviewing the risks and benefits of therapy. The references cited below offer helpful guidance on strategies for developing an individualized treatment plan.

• Shared decision making in “Glycemic Goals”: The ADA Standards of Medical Care in Diabetes 2023 Exit Disclaimer: You Are Leaving www.ihs.gov 
• Individualizing glycemic control targets using target ranges rather than single targets: The Veterans Administration/Department of Defense (VA/DoD) Clinical Practice Guideline for the Management of Type 2 Diabetes Mellitus in Primary Care.Exit Disclaimer: You Are Leaving www.ihs.gov