I take insulin glargine (Lantus) 14 U daily and currently use a 1 U:15 g carbohydrate ratio; with pre‑meal blood glucose values reaching 281 mg/dL and 514 mg/dL, what should my carbohydrate‑to‑insulin ratio and insulin‑sensitivity (correction) factor be?

Immediate Insulin Regimen Adjustment Required

Your current insulin regimen is dangerously inadequate—with blood glucose readings of 281 mg/dL and 514 mg/dL, you need immediate intensification to both basal insulin and addition of prandial coverage, along with aggressive correction of your carbohydrate ratio and insulin sensitivity factor.

Critical Problems with Current Regimen

Your Lantus dose of 14 units is far below what you need. For context, the American Diabetes Association recommends starting doses of 0.3-0.5 units/kg/day as total daily insulin for patients with severe hyperglycemia like yours 1. Blood glucose readings in the 280-514 mg/dL range indicate both inadequate basal coverage AND insufficient mealtime insulin 1.

Your 1:15 carbohydrate ratio (1 unit per 15 grams of carbohydrate) is likely too weak, and you appear to lack any correction factor protocol entirely 2, 3.

Recommended Insulin Adjustments

Basal Insulin (Lantus) Titration

• Increase Lantus by 4 units every 3 days until your fasting glucose consistently reaches 80-130 mg/dL 2, 1
• With fasting glucose ≥180 mg/dL, the 4-unit increment is specifically recommended rather than smaller adjustments 1
• Continue this aggressive titration until fasting targets are met 1
• Critical threshold: When your Lantus dose approaches 0.5 units/kg/day (roughly 35-40 units for most adults), you must add prandial insulin rather than continuing to escalate basal insulin alone 2, 1

Carbohydrate Ratio Correction

Your current 1:15 ratio is insufficient. A more appropriate starting point would be:

• Calculate using the 450 rule: 450 ÷ Total Daily Dose (TDD) = grams of carbohydrate covered by 1 unit 3
• If we estimate your TDD should be 40-50 units given your hyperglycemia, your ratio should be closer to 1:9 to 1:11 (1 unit per 9-11 grams of carbohydrate) 3
• Start with 1:10 as your new carbohydrate ratio and adjust by monitoring 2-hour post-meal glucose 2

Correction Factor (Insulin Sensitivity Factor)

You need an established correction protocol immediately:

• Calculate using the 1500 rule: 1500 ÷ TDD = mg/dL drop per 1 unit of insulin 2, 3
• With an estimated TDD of 40-50 units, your correction factor should be approximately 1:30 to 1:38 (1 unit lowers glucose by 30-38 mg/dL) 2, 3
• Start with 1:30 as your correction factor 2
• For glucose >250 mg/dL, add 2 units of rapid-acting insulin; for glucose >350 mg/dL, add 4 units 2, 1

Prandial Insulin Addition

Given your severe postprandial hyperglycemia (514 mg/dL reading), you need mealtime rapid-acting insulin:

• Start with 4 units of rapid-acting insulin (lispro, aspart, or glulisine) before your largest meal 2, 1
• Administer 0-15 minutes before eating 2
• Increase by 1-2 units every 3 days based on 2-hour post-meal glucose readings 2, 1
• Target post-meal glucose <180 mg/dL 2, 1

Daily Monitoring Requirements

• Check fasting glucose every morning to guide Lantus adjustments 1
• Check pre-meal glucose before each meal to calculate correction doses 1
• Check 2-hour post-meal glucose to assess carbohydrate ratio adequacy 2, 1
• Adjust doses every 3 days based on patterns, not single readings 2, 1

Critical Safety Warnings

Hypoglycemia Recognition

• Treat any glucose <70 mg/dL immediately with 15 grams of fast-acting carbohydrate 2, 1
• If hypoglycemia occurs without clear cause, reduce the implicated insulin dose by 10-20% 2, 1
• Always carry fast-acting carbohydrate sources 1

Common Pitfalls to Avoid

• Do NOT continue escalating Lantus beyond 0.5 units/kg/day without adding prandial insulin—this causes "overbasalization" with increased hypoglycemia risk 2, 1
• Do NOT rely on correction doses alone—you need scheduled basal and prandial insulin, with corrections as supplements only 2, 1
• Do NOT give rapid-acting insulin at bedtime as a sole correction dose—this markedly increases nocturnal hypoglycemia risk 2, 1

When to Contact Your Provider

• If fasting glucose remains >180 mg/dL after 2-3 weeks of titration 1
• If Lantus dose exceeds 0.5 units/kg/day without achieving targets 2, 1
• If you experience severe hypoglycemia (<54 mg/dL) or hypoglycemia unawareness 2
• If blood glucose readings consistently exceed 300 mg/dL despite adjustments 1

Foundation Therapy

• Continue metformin at maximum tolerated dose (up to 2000-2550 mg daily) unless contraindicated—this combination provides superior control with less weight gain 1
• The combination of metformin with intensive insulin therapy reduces total insulin requirements 1

Expected Outcomes

With proper basal-bolus therapy at weight-based dosing, you can expect:

• Fasting glucose 80-130 mg/dL within 2-4 weeks of aggressive titration 2, 1
• Post-meal glucose <180 mg/dL with appropriate prandial coverage 2, 1
• HbA1c reduction of 2-3% over 3-6 months with proper intensification 1