What to do if Hemoglobin A1C (HbA1C) increases in a patient on Lantus (insulin glargine) 40 units twice daily (BID), Humalog (insulin lispro) sliding scale, Jardiance (empagliflozin), and Jentadueto (linagliptin and metformin)?

Intensify Insulin Therapy and Optimize Foundation Medications

You need to increase the Lantus dose aggressively and add prandial insulin coverage before meals, while ensuring metformin is optimized to at least 2000mg daily. 1, 2

Immediate Action Steps

1. Increase Basal Insulin Dose

• Increase Lantus by 4 units every 3 days until fasting glucose reaches 80-130 mg/dL, since the current A1C of 8.0% indicates inadequate basal coverage 1, 2
• For a 127kg patient currently on 40 units BID (80 units total daily), this represents approximately 0.63 units/kg/day—already approaching the critical threshold where further basal escalation alone becomes counterproductive 1, 2
• Critical threshold warning: When basal insulin exceeds 0.5 units/kg/day (approximately 64 units for this patient), continuing to escalate basal insulin without adding prandial coverage leads to "overbasalization"—a dangerous pattern causing hypoglycemia and suboptimal control 1, 2

2. Add Structured Prandial Insulin Coverage

• Replace the sliding scale with scheduled prandial insulin starting with 4 units of Humalog before the largest meal, or use 10% of current basal dose (approximately 8 units) 1, 2
• Sliding scale (correction-only) insulin is inferior to scheduled basal-bolus regimens and should not be the primary prandial strategy 2
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on postprandial glucose readings 1, 2
• Gradually add prandial insulin to other meals if A1C remains elevated after 3-6 months 1

3. Optimize Metformin Dosing (Critical Foundation)

• Verify metformin dose is at least 2000mg daily (the dose in Jentadueto is only 1000mg BID maximum) 2
• Metformin should be continued and optimized even when intensifying insulin therapy, as it reduces total insulin requirements and provides complementary glucose-lowering effects 2
• Maximum effective dose is up to 2500mg/day 2

Clinical Signals of Overbasalization to Monitor

Watch for these warning signs that indicate you're using too much basal insulin without adequate prandial coverage 1, 2:

• Bedtime-to-morning glucose differential ≥50 mg/dL
• Basal insulin dose >0.5 units/kg/day (>64 units for this 127kg patient)
• Hypoglycemia episodes
• High glucose variability

Alternative: Consider GLP-1 RA Addition

If not already maximized, consider adding or intensifying a GLP-1 receptor agonist to the basal insulin regimen rather than continuing to escalate basal insulin alone 1, 2

• GLP-1 RAs provide superior A1C reduction compared to insulin glargine in patients with baseline A1C >9%, with less weight gain and hypoglycemia risk 3
• Fixed-ratio combinations (glargine/lixisenatide or degludec/liraglutide) can reduce medication burden while improving glycemic control 4

Monitoring Requirements

• Daily fasting blood glucose monitoring during titration phase 1, 2
• Check pre-meal and 2-hour postprandial glucose to guide prandial insulin titration 1
• Reassess A1C every 3 months during intensive titration 2
• If hypoglycemia occurs without clear cause, reduce the corresponding insulin dose by 10-20% immediately 1, 2

Common Pitfalls to Avoid

• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia—this leads to suboptimal control and increased hypoglycemia risk 1, 2
• Do not rely solely on sliding scale insulin—scheduled basal-bolus regimens are superior 2
• Do not discontinue metformin when intensifying insulin therapy unless contraindicated 2
• Do not delay adding prandial insulin when basal insulin approaches 0.5 units/kg/day and A1C remains elevated 1, 2