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- Glycemic Control: Assessment, Monitoring and Goal Setting
Diabetes Standards of Care and Resources for Clinicians and Educators
Glycemic Control: Assessment, Monitoring, and Goal Setting
The goal of glucose management is to reduce long-term complications of diabetes. There is strong evidence for the benefits of tight glucose control early in the course of diabetes. While intensive glycemic control in newly diagnosed patients is beneficial, tight control in the general diabetes population has not demonstrated the same benefits. It is important to achieve individualized glucose targets and to avoid poor glycemic control.
Two primary measures are available for health providers and patients to assess the effectiveness of glycemic control: A1C and patient self-monitoring of blood glucose (SMBG).
Clinical Practice Recommendations
Recommendations for Glycemic Control: Assessment, Monitoring, and Goal Setting
Recommendations for Glycemic Control
- Perform A1C testing every 3 to 6 months in "stable" patients to monitor progress toward clinical targets and facilitate therapeutic decision-making:
- A1C testing may be repeated as soon as 1 month later to assess response to initiation or a change in therapy.
- In patients with hemoglobinopathies or increased red cell turnover, (e.g., dialysis), consider using an alternative measure of glycemia (e.g., fructosamine) since A1C is less reliable in these patients.
A1C is a "weighted" measure of glycemic control over the preceding 120 days. The more recent days contribute a greater percentage to the measure than the distant days. Specifically, the mean level of blood glucose in the 30 days immediately preceding the test contributes approximately 50% of the final result.
Estimated Average Glucose (eAG)
The A1C test has been used to assess long-term management of diabetes for over a decade and many patients with diabetes are now familiar with it. However, because A1C is expressed as a percentage, it has been difficult for some patients to understand its significance and to relate their A1C number to other important diabetes measurements such as blood glucose expressed in mg/dL.
Health care providers can report A1C results to patients using eAG (estimated average glucose). The eAG uses the same units (mg/dL) that are used in home blood glucose measurements. For some patients, the eAG may be easier to understand than the A1C, and useful when discussing patients' glucose goals and results.
The table below shows the relationship between A1C and eAG. A calculator for converting A1C results into eAG, in either mg/dL or mmol/L. Exit Disclaimer: You Are Leaving www.ihs.gov
Correlation of A1C and Estimated Average Glucose (eAG) Results
|A1C %||eAG mg/dL|
|Source: ADA Standards of Medical Care in Diabetes—2017, p. S51.|
Some laboratories report eAG whenever an A1C is ordered. Providers at sites that do not receive the eAG in lab reports can use conversion estimates such as those provided in Table above.
Glycemic goals can be set using eAG since it may be easier for patients to assess whether goals are being reached every day when blood glucose is tested at home. The conversion table may help some patients make the connection between daily and long-term glucose control.
Recommendations for Self-Monitoring of Blood Glucose
- All insulin-treated patients should perform SMBG. If on multiple daily injections or an insulin pump, SMBG should be performed ≥ 3 times/day.
- The decision as to whether and how often to prescribe SMBG in non-insulin treated patients should be individualized. Providers are encouraged to consider SMBG when needed, such as when medication therapy is initiated or changed, in patients with any indication that their diabetes control is not stable (e.g., recent history of hypoglycemia), or in medically complex patients on multiple glucose-lowering medications.
- Prescribe the SMBG schedule so as to collect the information needed to adjust a patient's meal plan and medications, particularly insulin (e.g., check pre-supper values to see if the morning NPH insulin dose needs to be adjusted).
- Instruct patients clearly as to when and how often to check their blood glucose, and what to do with the results.
- Review SMBG data and A1C results with the patient at each diabetes visit, and take them into consideration when making therapeutic management decisions.
People with diabetes perform SMBG as a tool to help improve glycemic control. Since SMBG is expensive and can be burdensome for patients, research has been conducted to see if its effectiveness is worth its cost and inconvenience. The result has been general agreement that SMBG should be recommended for all insulin-treated patients with diabetes. The data are less clear, however, in patients treated with oral agents, and it is not known whether SMBG is useful in patients treated with diet alone.
Patients need hands-on instruction in how to use their glucose meter, including quality control. Training is more effective when patients are asked to demonstrate the correct procedure for checking blood glucose at the time of initial SMBG training, whenever they receive a new monitor, and periodically, to ensure they are still performing it correctly.
Recommendations for Setting Glycemic Control Goals
- In general, the A1C goal is < 7%. Consider:
- More stringent goals (e.g., < 6.5-7%) for younger, healthier patients
- Less stringent goals (e.g., 7-8%, 8-9%) for those with increased risks with tight control (see Veterans Administration/Department of Defense [VA/DoD] guidelines in Table below).
- The patient and provider discuss treatment goals and agree on a specific individualized target range of glycemic control after discussing the risks and benefits of therapy.
Benefits of Tight Glycemic Control
There is strong research evidence for the benefits of tight glucose control early in the course of diabetes. In the United Kingdom Prospective Diabetes Study (UKPDS), each 1% reduction in mean A1C was associated with reductions in risk of 21% for any end point related to diabetes, 21% for deaths related to diabetes, 14% for myocardial infarction, and 37% for microvascular complications.
In a 10-year follow-up of the more than 5,000 newly diagnosed people with diabetes who had been enrolled in the UKPDS, significantly greater risk reductions in microvascular disease, myocardial infarction, and mortality were noted in the intensive therapy group than in the conventional therapy group. These results were observed even though there were no longer differences in glycemic control soon after the main study ended. This finding has been referred to as a "legacy effect", providing credible evidence for the importance of intensive therapy early in the course of diabetes to help reduce the risk of complications later in the patient's life.
Risks of Tight Glycemic Control
While intensive glycemic control in newly diagnosed patients is beneficial, tight control in the general diabetes population has not demonstrated the same benefits. Clinical trials, including Action to Control Cardiovascular Risk in Diabetes (ACCORD), Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE), and Veterans Affairs Diabetes Trial (VADT), have shown that the risks of tight glycemic control include severe hypoglycemia and increased mortality. Further, a recent meta-analysis concluded that intensive glycemic control does not significantly reduce risk for all-cause or cardiovascular mortality, non-fatal myocardial infarction, composite microvascular complications, or retinopathy.
Note: While the risks of intensive control outweigh the benefits for some patients, it is still important to achieve individualized glucose targets and to avoid poor glycemic control.
Individualizing Glycemic Control Targets
Given the risks and lack of benefits of intensive control for many people with diabetes, the ADA Standards of Medical Care in Diabetes—2017 (p. S41) recommends that:
"...less stringent A1C goals may be appropriate for patients with a history of severe hypoglycemia, limited life expectancy, advanced microvascular or macrovascular complications, extensive comorbid conditions, and those with longstanding diabetes in whom the general goal is difficult to attain despite diabetes self-management education, appropriate glucose monitoring, and effective doses of multiple glucose-lowering agents including insulin."
One approach for individualizing glycemic control targets is to use target ranges rather than single targets. As shown in the Table below, the Veterans Administration/Department of Defense (VA/DoD) Diabetes Practice Guidelines Working Group recommends these target ranges: from < 7%, 7-8%, and 8-9%.
Using ranges allows for the flexibility needed for patient safety. In addition, ranges are used because they better account for the limitations of A1C testing accuracy, particularly in some Clinical Laboratory Improvement Amendments (CLIA)-waived testing methods (e.g., point-of-care tests) that cannot reliably detect small changes in A1C. This may result in overestimation of A1C with consequent unwarranted intensification of therapy resulting in an increased likelihood of hypoglycemia.
A1C Target Recommendations, VA/DoD Diabetes Practice Guidelines, 2010
|Major Comorbidity a
Absent or Mild b
> 10 years of life expectancy
|< 7||< 8||8-9 e|
5-10 years of life expectancy
|< 8||< 8||8-9 e|
< 5 years of life expectancy
|8-9 e||8-9 e||8-9 e|
|Source: VA/DoD Clinical Practice Guideline for the Management of Diabetes Mellitus, 2010. Exit Disclaimer: You Are Leaving www.ihs.gov|
Footnotes for Table:
- Major comorbidity includes, but is not limited to, any or several of the following active conditions: significant cardiovascular disease, severe chronic kidney disease, severe chronic obstructive pulmonary disease, severe chronic liver disease, recent stroke, and life-threatening malignancy.
- Mild microvascular disease is defined by early background retinopathy, and/or microalbuminuria, and/or mild neuropathy.
- Moderate microvascular disease is defined by preproliferative (without severe hemorrhage, intraretinal microvascular anomalies [IRMA], or venous bleeding) retinopathy, or persistent, fixed proteinuria (macroalbuminuria), and/or demonstrable peripheral neuropathy (sensory loss).
- Advanced microvascular disease is defined by severe nonproliferative (with severe hemorrhage, IRMA, or venous bleeding) or proliferative retinopathy, and/or renal insufficiency (serum creatinine level, > 2.0 mg/dL), and/or insensate extremities or autonomic neuropathy (for example, gastroparesis, impaired sweating, or orthostatic hypotension).
- Further reductions may be appropriate, balancing safety and tolerability of therapy.
- Major comorbidity is present, but is not end-stage and management is achievable.
- Major comorbidity is present and either is end-stage or management is significantly challenging.
Performance Indicators, Standards of Care, and Individualized Targets
It is important that providers distinguish between performance indicators, standards of care, and the need to individualize patient goals.
- Performance indicators such as the Government Performance and Results Act (GPRA) are established by a government agency or other official entity to evaluate the clinical performance of providers. These indicators compare clinical measures (e.g., A1C or blood pressure) of patient panels against a benchmark.
- Standards of care refer to clinical goals set by professional organizations (e.g., ADA) based on the best science available at the time. The standards of care set the goals for patients, in general, as well as the standards by which clinical care should be judged.
Note: However, neither performance indicators nor standards of care should be understood to dictate the clinical goals for a particular patient, especially those whose medical conditions make achieving such goals unwise or even unsafe.
Treatment for Achieving Glycemic Control Targets
As with setting glycemic control targets, treatment plans for achieving targets must be individualized for each patient. In general, recommended first line therapy upon diagnosis includes lifestyle therapy and metformin.
Clinician and Educator Resources
Featured Glycemic Control Resources
Patient Education Resources
Glycemic Control Patient Education Resources
Education Materials and Resources (Online Catalog):
Glycemic Control: Assessment, Monitoring, and Goal Setting CME Trainings
|Session Title||Session Material||CME/CE Information|
|New Diabetes Update: Roles and Benefits of SGLT-2 Inhibitors and GLP-1 Agonists Exit Disclaimer: You Are Leaving www.ihs.gov
Paul Bloomquist, MD
Area Diabetes Consultant
Phoenix Area IHS
(Originally presented on 09/21/21.)