Diabetes mellitus type 2 Glycemic control

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2] Anahita Deylamsalehi, M.D.[3]

See also Glycemic Targets in Diabetes

Overview

Glycemic control is an important measure in diabetes treatment. There are general rules for glycemic control but they should be individualized for every patients based on provider decision and patient condition. HbA1c is one of the diagnostic tools with a strong predictive value for diabetes and also a laboratory method with 3 months average glycemic control. There are several guidelines defined glycemic goals. To name one, ADA has suggested certain range of HbA1C for diabetic patients in order to have less complications and better prognose.

Measuring glycemic control

Main article: Blood glucose monitoring

(see also section on Continuous Blood Glucose Monitoring below)

• Hb A1C reflects average glycemia over approximately 3 months and has strong predictive value for diabetes complications. Therefore, HbA1C should be measured as baseline control and every 3 months to see whether the treatment goals have been achieved and maintained.
• ALternative measurements include:
  • Fructosamine and glycated albumin can show mean blood glucose level over three weeks.
  • 1,5-Anhydroglucitol can reflect hyperglycemic changes in days to weeks.

Self-monitoring blood glucose (SMBG)

• Blood glucose, via self-monitoring of blood glucose (SMBG) is accurate and easy to use by patients. It allows patients to evaluate their individual response to therapy and assess whether glycemic targets are being achieved. SMBG is mostly used for patients with type 1 diabetes mellitus but some patients with type 2 diabetes who require basal insulin will benefit from this method of monitoring.

• It is not clear that home monitoring is helpful in non-insulin treated diabetes mellitus type 2..
  • One randomized controlled trial found that self-monitoring of blood glucose did not improve the Hba1c among "reasonably well controlled non-insulin treated patients with type 2 diabetes".
  • A more recent meta-analysis did not find benefit in home monitoring.

• The following video shows how to apply glucometer devices for SMBG:

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Continuous glucose monitoring

• The Miao Miao is a smartreader add on for the d-Nav that sends reading to a smartphone.
• Libre only tells you what your blood sugar was in the past.
• The d-Nav Insulin Guidance System (Hygieia, Livonia, MI, USA) has shown benefit in a randomized controlled trial..

Goals

Evidence from trials

Forest Plot showing meta-analysis of randomized controlled trials of differing target glucose control and mortality for diabetes mellitus type 2. Note the heterogeneity due to increased death when the glycosylated hemoglobin A (Hb A1c) target was 6.0% in the ACCORD trial

A systematic review of trials published through 2010 did not find clear benefit in mortality from type glucose control.

• A goal fasting blood glucose of below 108 mg/dl (6 mmol/L) over 10 years resulting in an Hb A1c of 7% over 10 years was found in the United Kingdom Prospective Diabetes Study (UKPDS 33) randomized controlled trial. Intensive control reduced diabetic complications in one out of every 20 patients (number needed to treat = 20).
• A goal fasting blood glucose of below 108 mg/dl (6 mmol/L) over 10 years resulting in an Hb A1c of 7.4% over 10.7 years in the metformin group compared to 8.0% in the conventional group in the UK Prospective Diabetes Study (UKPDS 34) randomized controlled trial. Metformin reduced cardiovascular disease in one out of every 11 patients (number needed to treat = 11).
• A Hb A1c of 6.9% over 6 years was found in the VA Diabetes Trial (VADT) randomized controlled trial to have no significant effect on diabetic complications. Although the treatment group averaged an Hb A1c of 6.9%, the goal was 6.0%.
• A Hb A1c goal of 6.5% over 5 years was found in the ADVANCE randomized controlled trial not to reduce mortality using a protocol whose first step was a sulfonylurea (gliclazide). The intervention group had 0.9% less nephropathy, but more severe hypoglycemia.
• A Hb A1c goal of 6% over 3.5 years was found in the ACCORD randomized controlled trial found to increase serious complications.
• The ORIGIN trial used basal insulin supplementation to reduce the Hb A1c from 6.4% to 6.2%. There was no benefit on cardiac outcomes but there was an increase in hypoglycemia and weight gain.
• The PROACTIVE study used pioglitazone.
• The older University Group Diabetes Program (UGDP) also found no benefit in a controversial randomized controlled trial. The UGDP randomized approximately 1000 patients to one of five treatment groups and followed from 1962 to 1975: phenformin, tolbutamide, small fixed-dose insulin (ISTD) based on body-surface area (averaged 14 units per day), variable-dose insulin (ISTD) (averaged 45 units per day), n (IVAR), or placebo. The trial found statistically significant increase in cardiovascular deaths among the patients treated with tolbutamide and so this group was stopped in 1969. The phenformin group was also stopped early due to increased mortality. The ISTD group had no reduction in blood glucose. The IVAR group had a reduction in the IVAR group of about 2.0 mmol/L (36 mg/dL) which correlates to a 1% difference in the level of Hb A1c. Problems in the trial include: 1) "25% of placebo and tolbutamide-treated subjects dropped out or changed medication during the trial, 2) glucose values were only checked quarterly, 3) smoking history was not measured 4) reduced fraction of males in the IVAR group (IVAR=22%; placebo=31%).

Clinical Practice Guidelines

• There are opposing guidelines between the American College of Physicians (ACP) and the American Diabetes Association (ADA) on the goal for the HbA1c. Taking these guidelines into consideration, it is important to use a guideline which is an evidence-based instruction and also a clinically practical one. that updated guidelines from 2019 of the guideline
  • The American College of Physicians published clinical practice guidelines in 2018 that states:
    • "clinicians should aim to achieve an HbA1c level between 7% and 8% in most patients with type 2 diabetes and should consider de-intensifying pharmacologic therapy in patients with type 2 diabetes who achieve HbA1c levels less than 6.5%."
  • The American Diabetes Association (ADA) published clinical practice guidelines in 2020 and released a response statement in opposition to the ACP's guidelines:
    • “An HbA1C goal for many nonpregnant adults of <7% is appropriate”
    • On the basis of provider judgement and patient preference, achievement of lower HbA1C levels (such as <6.5%) may be acceptable if this can be achieved safely without significant hypoglycemia or other adverse effects of treatment”
    • “Less stringent HbA1C goals may be appropriate for patients with a history of severe hypoglycemia, limited life expectancy, advanced microvascular or macrovascular complications, extensive comorbid conditions, or long-standing diabetes in whom the goal is difficult to achieve despite diabetes self-management education, appropriate glucose monitoring, and effective doses of multiple glucose-lowering agents including insulin”
    • Regarding assessment of the trustworthiness of the methods, the ADA did not list author names, provide a statement of conflicts of interest nor describe methods or breadth of peer review.
• Kaiser Permanente states:
  • A1C goal of 7.0–8.0%
  • "Use clinical judgment to determine if a target lower than 7.0% is appropriate for an individual patient. It can be challenging to push a patient’s HbA1c levels from just above 7.0% to below 7.0%. There are potential benefits (decreased nonfatal myocardial infarction) and potential harms (hypoglycemia, weight gain, and possible increase in all-cause and cardiovascular-cause mortality) of intensive glucose therapy, especially in patients with known cardiovascular disease."
  • "For frail elderly patients, a target HbA1c of 7.0–9.0% is reasonable"
• Based on American Diabetes Association (ADA) and American Association of Clinical Endocrinologists (AACE), the glucose concentration goal for critically ill patients recommended to be 140–180 mg/dL. On the other hand the aforementioned associations advocate a lower goal for glucose concentration (110–140 mg/dl) in selected ICU patients at hospitals with expert medical team. Measures above 180 mg/dl or lower than 110 mg/dl have been should be avoided due to high chance of serious adverse effects. Conversely, when there is no chance of supervision or recurrent blood glucose control in terminally ill patients, measures up to 200 mg/dl are also accepted.
• Based on American Diabetes Association (ADA), American Association of Clinical Endocrinologists (AACE) and Endocrine Society guidelines the recommended pre-meal glucose concentration goal for non-critically ill patients is less than 140 mg/dL. On the other hand, the recommended random glucose concentration goal for non-critically ill patients is less than 180 mg/dL.
• Based on Joint British Diabetes Societies (JBDS) the recommended glucose concentration goal for inpatients is 108–180 mg/dL. The aforementioned guideline questions lower glucose concentrations, due to high risk of hypoglycemia.

Frequency goals are achieved

Typical practice:

• 35% of patients have an HbA1c of less than 7 per HEDIS measures:
• 59% according to NHANES (self-reported by patients)

Best practice

• 71% in the Veterans Affairs VISN16.
• 69% according to Kaiser in Colorado. However, this is the proportion of patients "ever achieving" goal and not clear is this is equivalent to a cross-section of patients at goal.