What is the best course of treatment for a patient with hyperglycemia (elevated fasting blood sugar level of 17.8 mmol/L)?

Immediate Insulin Therapy Required for Severe Hyperglycemia

For a fasting blood sugar of 17.8 mmol/L (320 mg/dL), initiate basal insulin immediately at 10 units once daily or 0.1-0.2 units/kg body weight, and titrate aggressively by 4 units every 3 days until fasting glucose reaches 4.4-7.2 mmol/L (80-130 mg/dL). 1

Why Insulin is Necessary Now

Your fasting blood sugar of 17.8 mmol/L (320 mg/dL) meets the threshold for immediate insulin initiation. It is common practice to start insulin therapy for patients who present with blood glucose levels ≥16.7 mmol/L (300 mg/dL), especially if symptoms of hyperglycemia (polyuria, polydipsia) or evidence of catabolism (weight loss) are present. 1 At this level of hyperglycemia, oral medications alone are insufficient—insulin is the most effective agent when glucose is severely elevated. 1

Starting Insulin Regimen

• Begin with basal insulin (insulin glargine/Lantus or similar long-acting insulin) at 10 units once daily, administered at the same time each day. 1, 2
• Alternatively, use weight-based dosing of 0.1-0.2 units/kg/day for initial therapy. 1, 2
• Continue metformin unless contraindicated (kidney function with eGFR <30 mL/min), as the combination reduces total insulin requirements and provides complementary glucose-lowering effects. 1, 3

Aggressive Titration Protocol

Because your fasting glucose is ≥16.7 mmol/L (≥300 mg/dL), use the aggressive titration schedule: 1, 2

• Increase basal insulin by 4 units every 3 days until fasting glucose consistently reaches 4.4-7.2 mmol/L (80-130 mg/dL). 1, 2
• If fasting glucose drops to 7.8-9.9 mmol/L (140-179 mg/dL), reduce increments to 2 units every 3 days. 1, 2
• If hypoglycemia occurs (glucose <3.9 mmol/L or <70 mg/dL), immediately reduce the dose by 10-20% and determine the cause. 1, 2

Daily Monitoring Requirements

• Check fasting blood glucose every morning during the titration phase—this is essential for safe dose adjustments. 1, 2
• Self-monitoring allows you to implement self-titration algorithms, which improve glycemic control faster than waiting for clinic visits. 1, 2

When to Add Mealtime Insulin

If after 3-6 months your fasting glucose reaches target but HbA1c remains above 7%, or if your basal insulin dose exceeds 0.5 units/kg/day without achieving goals, add prandial (mealtime) insulin rather than continuing to escalate basal insulin alone. 1, 2

• Start with 4 units of rapid-acting insulin before your largest meal, or use 10% of your current basal dose. 1, 2
• This prevents "overbasalization"—a dangerous pattern where excessive basal insulin causes hypoglycemia without improving overall control. 1, 2

Critical Pitfalls to Avoid

• Do not delay insulin initiation hoping oral medications will suffice—at 17.8 mmol/L, only insulin can rapidly reverse glucose toxicity and prevent metabolic decompensation. 1
• Do not stop metformin when starting insulin unless contraindicated—continuing metformin reduces insulin requirements by 20-30% and limits weight gain. 1, 3
• Do not rely on sliding scale (correction) insulin alone—scheduled basal insulin with correction doses as adjunct is the proper approach. 1

Expected Outcomes

• With appropriate insulin therapy, you should see fasting glucose drop to target range within 2-4 weeks of aggressive titration. 1, 2
• As glucose toxicity resolves, your beta cells may recover some function, potentially allowing simplification of the regimen later. 1
• Early intensive treatment prevents long-term complications—every week of uncontrolled hyperglycemia increases your risk of microvascular damage. 1, 4

Follow-Up Timeline

• Recheck HbA1c after 3 months to assess overall glycemic control. 1, 5
• Reassess your insulin regimen at every visit, looking for signs you need prandial insulin or can simplify therapy. 1, 2
• Once fasting glucose stabilizes at target, continue daily monitoring but reduce frequency based on stability. 1, 2