How to correct hyperglycemia?

How to Correct High Blood Sugar (Hyperglycemia)

Immediate Assessment and Initial Action

The approach to correcting hyperglycemia depends critically on the severity of presentation and whether the patient has symptoms of metabolic decompensation. 1

Severe Hyperglycemia Requiring Urgent Insulin

If blood glucose is ≥250 mg/dL (13.9 mmol/L) with ketosis/ketoacidosis, or if there are symptoms of severe hyperglycemia (marked polyuria, polydipsia, weight loss), initiate insulin therapy immediately to rapidly correct the metabolic derangement. 1

• In adults with HbA1c ≥10% (86 mmol/mol), especially with weight loss or ketonuria, insulin should be the preferred initial agent 1
• In youth with marked hyperglycemia (blood glucose ≥250 mg/dL, HbA1c ≥8.5%) without acidosis but with symptoms, start basal insulin while simultaneously initiating metformin 1
• For ketoacidosis, use subcutaneous or intravenous insulin to correct hyperglycemia and metabolic derangement; once acidosis resolves, continue subcutaneous insulin while adding metformin 1

Moderate Hyperglycemia (HbA1c 8.5-10% or 69-86 mmol/mol)

For patients with HbA1c >8.5% but <10% without severe symptoms, consider initial combination therapy with metformin plus additional glucose-lowering agents rather than stepwise monotherapy. 1

• Metformin is the foundational pharmacologic treatment if kidney function is normal 1
• Start metformin at 500-850 mg once or twice daily with meals, titrating up by 500-850 mg every 1-2 weeks to maximum effective dose of 2000-2550 mg/day divided in 2-3 doses 1, 2
• Add GLP-1 receptor agonist therapy before considering insulin in most patients, as this allows lower glycemic targets with lower injection burden and reduced hypoglycemia and weight gain risk compared to insulin alone 1
• In youth ≥10 years old not meeting goals with metformin, add liraglutide (if no personal/family history of medullary thyroid carcinoma or MEN2) and/or empagliflozin 1

Mild to Moderate Hyperglycemia (HbA1c <8.5% or <69 mmol/mol)

For incidentally diagnosed or metabolically stable patients with HbA1c <8.5%, initiate metformin as first-line pharmacologic therapy alongside intensive lifestyle intervention. 1

• Metformin primarily reduces hepatic glucose production, directly addressing fasting hyperglycemia 3, 4
• Metformin rarely causes hypoglycemia by itself, though risk increases if patient doesn't eat enough, drinks alcohol, or takes other glucose-lowering medications 2

Insulin Initiation and Titration Strategy

When insulin is indicated, add basal insulin to existing therapy rather than substituting it. 1

Starting Basal Insulin

• Begin with 10 units daily or 0.1-0.2 units/kg/day of long-acting basal insulin (insulin glargine or similar) 5
• Discontinue sulfonylureas once insulin is started to avoid hypoglycemia 1
• Target fasting glucose of 70-130 mg/dL (3.9-7.2 mmol/L) 1

Titration Protocol

• Increase basal insulin by 2-4 units every 3-7 days based on fasting blood glucose values until target is achieved 1, 5
• Monitor fasting blood glucose daily during titration 5
• If hypoglycemia occurs (glucose <70 mg/dL), reduce insulin dose by 10-20% 1, 5
• Check HbA1c every 3 months to assess response 1, 5

When to Intensify Beyond Basal Insulin

If basal insulin reaches 0.5 units/kg/day or 1.5 units/kg/day without achieving HbA1c goal, consider adding prandial insulin or maximizing non-insulin therapies. 1, 5

• Add prandial insulin starting with 4 units or 10% of basal dose with the largest meal 1
• Alternatively, add or optimize GLP-1 receptor agonist therapy before intensifying insulin further 1
• Consider fixed-ratio combination products (insulin degludec/liraglutide or insulin glargine/lixisenatide) for patients on both basal insulin and GLP-1 RA 1

Essential Lifestyle Interventions

Lifestyle modifications must be implemented immediately and reinforced at every visit, regardless of pharmacologic therapy. 1, 6

Dietary Modifications

• Focus on nutrient-dense, high-quality foods: non-starchy vegetables, whole fruits, legumes, whole grains, nuts, seeds, and low-fat dairy 1, 7
• Reduce calorie-dense, nutrient-poor foods, particularly sugar-added beverages, sweets, refined grains, and processed/ultra-processed foods 1, 7
• Target 5-10% body weight loss, which meaningfully improves insulin sensitivity and glycemic control 3, 6

Physical Activity

• Prescribe at least 60 minutes daily of moderate-to-vigorous physical activity for youth (with muscle and bone strengthening ≥3 days/week) 1
• For adults, recommend at least 150 minutes per week of moderate-intensity activity including aerobic exercise, resistance training, and flexibility exercises 3
• Decrease sedentary recreational screen time 1

Monitoring and Reassessment

Review response to all therapies at regular intervals, including impact on HbA1c, weight, safety, and organ protection. 1

• Check HbA1c every 3 months until <7% (or individualized target), then at least every 6 months 1
• Assess adequacy of insulin dose at every visit, looking for signs of overbasalization (elevated bedtime-to-morning differential, hypoglycemia, high glucose variability) 1
• Avoid therapeutic inertia—re-evaluate health behaviors, medication-taking behaviors, and side effects at every clinic visit 1

De-intensification Considerations

Some patients require medication reduction or discontinuation, particularly when therapy is ineffective, causes side effects, or when glycemic goals change. 1

• If HbA1c falls below 6.5% (48 mmol/mol) or substantially below individualized target, reduce or stop medications associated with hypoglycemia risk 1
• In patients initially treated with insulin who meet glucose goals, taper insulin over 2-6 weeks by decreasing dose 10-30% every few days 1
• Consider de-intensification in frail older adults and those with glycemic metrics substantially better than target 1

Critical Pitfalls to Avoid

• Do not delay insulin initiation when HbA1c is ≥10%—prolonged severe hyperglycemia increases complication risk and may indicate type 1 diabetes 1, 5
• Do not start with inadequate insulin doses (e.g., 6 units is likely subtherapeutic)—use appropriate starting doses of 10 units or 0.1-0.2 units/kg/day 5
• Do not add prandial insulin prematurely before optimizing basal insulin—this increases complexity, cost, and hypoglycemia risk without addressing inadequate basal coverage 5
• Do not substitute glucose-lowering therapies when intensifying—incorporate agents with complementary mechanisms of action rather than replacing existing effective therapies 1
• Do not continue sulfonylureas once insulin is started—this significantly increases hypoglycemia risk 1
• Do not dismiss the importance of lifestyle interventions even when intensifying pharmacologic therapy—diet and exercise remain essential throughout treatment 1, 6