What is the recommended management for elevated fasting blood glucose levels?

Management of Elevated Fasting Blood Glucose Levels

For most patients with elevated fasting blood glucose, initiate treatment at a threshold of ≥180 mg/dL (10.0 mmol/L) and target a glucose range of 140-180 mg/dL (7.8-10.0 mmol/L). 1

Diagnostic Thresholds and Targets

• Fasting plasma glucose ≥126 mg/dL indicates diabetes mellitus, while values between 100-125 mg/dL indicate impaired fasting glucose 2
• For hospitalized patients with hyperglycemia, treatment should be initiated when glucose levels reach ≥180 mg/dL (checked on two occasions) 1
• Target glucose ranges should be:
  • 140-180 mg/dL (7.8-10.0 mmol/L) for most critically ill and non-critically ill patients 1
  • More stringent goals of 110-140 mg/dL (6.1-7.8 mmol/L) may be appropriate for selected patients (e.g., cardiac surgery patients) if achievable without significant hypoglycemia 1
  • For non-critically ill patients, a target range of 100-180 mg/dL (5.6-10.0 mmol/L) is recommended 1

Management Algorithm for Outpatients

Step 1: Lifestyle Modifications

• Implement dietary changes:
  • Reduce total fat to <30% of calories, saturated fat to <10% of calories, cholesterol to <300 mg/day, and avoid trans fats 1
  • Decrease intake of simple sugars 1
  • Increase consumption of fruits and vegetables 1
• Promote physical activity with a goal of at least 1 hour of active play per day 1
• Achieve appropriate weight management with 5-10% weight loss for those who are overweight 1

Step 2: Pharmacological Therapy

• For type 2 diabetes with elevated fasting glucose:

  • Metformin should be initiated concurrently with lifestyle intervention at diagnosis 1, 3
  • If fasting glucose remains elevated after 3 months on metformin, consider adding one of the following: sulfonylurea, TZD, DPP-4 inhibitor, GLP-1 receptor agonist, or basal insulin 1
  • For severely uncontrolled diabetes (fasting glucose >250 mg/dL, random glucose consistently >300 mg/dL, or HbA1c >10%), insulin therapy in combination with lifestyle intervention is the treatment of choice 1

• For impaired fasting glucose (100-125 mg/dL):

  • Implement reduced-calorie diet and increased activity aimed at 5-10% decrease in weight over 6 months 1
  • If repeat fasting glucose remains 100-126 mg/dL, consider insulin-sensitizing medication per endocrinologist 1
  • Metformin has been shown to delay or prevent the onset of diabetes in those with impaired fasting glucose 2

Special Considerations

Hospital Management

• For critically ill patients with hyperglycemia, continuous insulin infusion is the preferred regimen 1
• For non-critically ill hospitalized patients, basal-bolus insulin regimens are recommended 1
• For patients receiving glucocorticoid therapy, which can induce hyperglycemia, consider:
  • For short-acting glucocorticoids (e.g., prednisone): prandial insulin dosing, often with intermediate-acting (NPH) insulin 1
  • For long-acting glucocorticoids: long-acting insulin may be required to control fasting blood glucose 1

Perioperative Care

• Target blood glucose range should be 80-180 mg/dL (4.4-10.0 mmol/L) 1
• Withhold metformin on the day of surgery 1
• Withhold oral glucose-lowering agents the morning of surgery 1
• Give half of NPH dose or 60-80% doses of long-acting insulin 1
• Monitor blood glucose at least every 4-6 hours while patient is taking nothing by mouth 1

Monitoring and Follow-up

• Regular monitoring of fasting plasma glucose is essential to assess treatment efficacy 4
• For patients with diabetes, HbA1c targets should generally be <7%, but may be individualized based on risk of hypoglycemia and comorbidities 1
• Controlling fasting hyperglycemia is crucial as it:
  • Minimizes glucotoxicity and insulin resistance 4
  • Profoundly influences daytime glycemic control 4
  • Reduces risk of diabetes complications 4

Importance of Controlling Fasting Hyperglycemia

• Even brief periods of hyperglycemia increase the risk of microvascular and macrovascular complications 4
• Higher fasting plasma glucose levels, even within the normoglycemic range (<100 mg/dL), constitute an independent risk factor for developing type 2 diabetes 5
• Normalization of fasting blood glucose profoundly reduces the risk of diabetes complications 4
• Diabetes doubles the risk for stroke, and approximately 20% of patients with diabetes will die of stroke 1

Remember that fasting hyperglycemia is a phenomenon observed in essentially all individuals with diabetes and may be due to dysregulation of normal circadian hormonal patterns resulting in increased hepatic glucose output 4. Controlling hepatic glucose output and disposal is essential for effectively managing fasting hyperglycemia.