What are the geilines for adjusting basal insulin (long-acting insulin) in a patient with type 2 diabetes mellitus?

Adjusting Basal Insulin in Type 2 Diabetes

Start basal insulin at 10 units once daily (or 0.1-0.2 units/kg), then increase by 2-4 units every 3 days based on fasting glucose until reaching 80-130 mg/dL, but stop escalating when the dose exceeds 0.5 units/kg/day and add prandial insulin instead. 1

Initial Dosing

• Begin with 10 units once daily or 0.1-0.2 units/kg body weight administered at the same time each day (bedtime or with evening meal). 2
• Continue metformin unless contraindicated, and possibly one additional non-insulin agent. 2, 1
• For severe hyperglycemia (blood glucose ≥300-350 mg/dL or A1C ≥10-12% with symptoms), consider starting with 0.3-0.5 units/kg/day as basal-bolus therapy immediately rather than basal insulin alone. 2, 1

Systematic Titration Protocol

The titration schedule depends on fasting glucose levels:

• If fasting glucose ≥180 mg/dL: Increase by 4 units every 3 days 1
• If fasting glucose 140-179 mg/dL: Increase by 2 units every 3 days 1
• Target fasting glucose: 80-130 mg/dL 1

Alternative approach: Increase by 10-15% of the current dose once or twice weekly until target is reached. 2, 1

• Equip patients with self-titration algorithms based on self-monitoring of blood glucose—this improves glycemic control significantly. 2

Hypoglycemia Management During Titration

• If hypoglycemia occurs without clear cause: Reduce dose by 10-20% immediately. 1
• If >2 fasting glucose values per week are <80 mg/dL: Decrease basal insulin by 2 units. 1

Critical Threshold: When to Stop Escalating Basal Insulin

This is the most important clinical decision point to prevent "overbasalization":

• When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin rather than continuing to escalate basal insulin alone. 1

Clinical signals of overbasalization include: 1

• Basal insulin dose >0.5 units/kg/day
• Bedtime-to-morning glucose differential ≥50 mg/dL
• Hypoglycemia episodes
• High glucose variability

Adding Prandial Insulin (When Basal Insulin is Insufficient)

Add prandial insulin when: 1

• Basal insulin is optimized (fasting glucose 80-130 mg/dL) but A1C remains above target after 3-6 months
• Basal insulin dose approaches 0.5-1.0 units/kg/day without achieving A1C goal

Starting prandial insulin dose: 1

• 4 units of rapid-acting insulin before the largest meal, OR
• 10% of the current basal insulin dose per meal (if A1C <8%)

Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on postprandial glucose readings. 1

Alternative to Prandial Insulin

• Consider adding a GLP-1 receptor agonist to the basal insulin regimen to improve A1C while minimizing weight gain and hypoglycemia. 1
• This combination provides potent glucose-lowering with less weight gain and hypoglycemia than intensified insulin regimens. 2, 1

Foundation Therapy Considerations

• Continue metformin when initiating or intensifying insulin therapy—it reduces weight gain, lowers insulin requirements, and decreases hypoglycemia risk. 1, 3
• Discontinue sulfonylureas, DPP-4 inhibitors, and GLP-1 receptor agonists once more complex insulin regimens beyond basal are used. 2
• Consider adding SGLT2 inhibitors or pioglitazone in patients with suboptimal control requiring increasing insulin doses—these can improve control and reduce total insulin needed. 2

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during titration. 1
• Assess insulin dose adequacy at every clinical visit, looking for signs of overbasalization. 1
• Check A1C every 3 months during intensive titration. 1

Common Pitfalls to Avoid

• Do not delay insulin initiation in patients failing to achieve glycemic goals on oral medications—this prolongs hyperglycemia exposure and increases complication risk. 1, 3
• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia—this leads to overbasalization with suboptimal control and increased hypoglycemia risk. 1
• Do not use insulin as a threat or describe it as punishment—explain the progressive nature of type 2 diabetes objectively. 2
• Do not abruptly discontinue oral medications when starting insulin—continue metformin unless contraindicated. 1, 4

Patient Education Essentials

Comprehensive education must include: 2, 1

• Blood glucose self-monitoring techniques
• Hypoglycemia recognition and treatment (15 grams of fast-acting carbohydrate for glucose ≤70 mg/dL)
• Proper insulin injection technique and site rotation
• Nutrition management
• "Sick day" management rules
• Insulin storage and handling

Special Populations

Hospitalized patients (insulin-naive): 1

• Start with 0.3-0.5 units/kg/day total daily dose
• Give 50% as basal insulin and 50% as rapid-acting insulin before meals
• Use lower doses (0.3 units/kg/day) for high-risk patients (elderly >65 years, renal failure, poor oral intake)

Patients on high-dose home insulin (≥0.6 units/kg/day): 1

• Reduce total daily dose by 20% upon hospitalization to prevent hypoglycemia