How to manage a patient with severe hyperglycemia (A1c of 13) using Lantus (insulin glargine) and Humalog (insulin lispro)?

Managing Severe Hyperglycemia (A1c 13%) with Basal-Bolus Insulin

For a patient with A1c of 13%, you should immediately initiate dual therapy with basal insulin (Lantus/glargine) AND add metformin, while using prandial insulin (Humalog/lispro) for meal coverage to rapidly correct this severe hyperglycemia. 1

Initial Assessment and Exclusion of Acute Complications

Before initiating treatment, you must immediately assess for:

• Ketosis/ketoacidosis - Check for symptoms (nausea, vomiting, abdominal pain), urine or serum ketones, and metabolic acidosis 2
• Hyperosmolar hyperglycemic state (HHS) - If blood glucose ≥600 mg/dL, evaluate for HHS with serum osmolality, mental status changes, and severe dehydration 2, 3
• Precipitating factors - Infection, medication non-adherence, acute illness, or cardiovascular events 3

If ketoacidosis is present, initiate IV or subcutaneous insulin immediately to correct the metabolic derangement, then transition to the regimen below once acidosis resolves 2.

Starting Insulin Regimen

Basal Insulin (Lantus/Glargine)

• Initial dose: 0.5 units/kg/day administered once daily (typically at bedtime) 1
• For a 70 kg patient, this would be approximately 35 units daily
• Titrate every 2-3 days based on fasting blood glucose, targeting 80-130 mg/dL 1

Prandial Insulin (Humalog/Lispro)

• Initiate basal-bolus regimen with rapid-acting insulin before each main meal 2
• Start with approximately 4-6 units before each meal, or calculate as 50% of total daily insulin dose divided among three meals 3
• Adjust doses based on pre-meal and 2-hour post-meal glucose readings
• Target pre-meal glucose 80-130 mg/dL and post-meal <180 mg/dL

Metformin

• Start metformin 500 mg twice daily with meals if renal function is normal (eGFR >30 mL/min) 1
• Titrate up to 1000 mg twice daily (2000 mg total daily dose) over 1-2 weeks to minimize gastrointestinal side effects 1
• This is essential for long-term management and should be initiated simultaneously with insulin 2

Monitoring Protocol

• Blood glucose monitoring: Check fasting glucose daily and pre-meal/2-hour post-meal glucose at least 3-4 times daily initially 2
• A1c measurement every 3 months to assess glycemic control 2
• Insulin dose adjustments every 2-3 days based on glucose patterns 1
• Monitor for hypoglycemia, especially nocturnal episodes - the most common adverse effect with this regimen 4

Target A1c Goals

• Aim for A1c <7.0% (53 mmol/mol) for most patients on this regimen 2
• More stringent targets of <6.5% may be appropriate if achieved without significant hypoglycemia 2
• With an A1c of 13%, expect approximately 1-1.5% reduction per month with aggressive insulin therapy 1

Insulin Tapering Strategy

Once glycemic targets are consistently achieved (typically after 2-6 weeks):

• Reduce insulin by 10-30% every few days while continuing metformin 2
• Monitor glucose closely during tapering to ensure control is maintained
• Some patients may be able to transition to basal insulin alone or even oral agents only, depending on beta-cell function 2

Critical Pitfalls to Avoid

• Delaying insulin initiation - With A1c of 13%, metformin monotherapy will be completely insufficient 1
• Using only basal insulin without prandial coverage - At this level of hyperglycemia, basal insulin alone (even at doses up to 1.5 units/kg/day) will likely fail to achieve adequate control 2
• Inadequate insulin titration - Many patients remain above target because providers fail to titrate aggressively enough 5, 6
• Failing to add metformin - This is essential for long-term management and should not be omitted 2, 1
• Not monitoring for vitamin B12 deficiency with long-term metformin use 1
• Rapid glucose reduction causing cerebral edema - Avoid dropping glucose >100 mg/dL per hour 3

Expected Outcomes

With this aggressive basal-bolus regimen plus metformin:

• Expect A1c reduction of approximately 3-4% over 3-6 months 1
• Most patients should achieve A1c <7% within 6 months if adherent 2
• Weight gain of 2-3 kg is common with insulin intensification 4, 6
• Hypoglycemia risk increases but can be minimized with proper patient education and glucose monitoring 4

Alternative Consideration

If the patient fails to achieve targets on basal insulin up to 1.5 units/kg/day, transition to multiple daily injections with basal and premeal bolus insulin is mandatory 2. The combination of Lantus (once daily) and Humalog (three times daily before meals) represents this optimal basal-bolus strategy for severe hyperglycemia 6.