What adjustments should be made to the carb ratio, Lantus (Insulin Glargine) dose, and NPH (Neutral Protamine Hagedorn) insulin dose for a 72-year-old male patient with a BMI of 39, Impaired Renal Function (GFR of 25 mL/min/1.73m^2), on Lantus and Jardiance (Empagliflozin), presenting with elevated blood glucose levels?

Insulin Regimen Adjustment for Severe Hyperglycemia with Renal Impairment

Immediate Basal Insulin Intensification

Your patient requires aggressive upward titration of Lantus and immediate addition of prandial insulin coverage—the current regimen is grossly inadequate for blood glucose levels of 400 mg/dL. 1

Lantus Dose Adjustment

• Increase Lantus immediately to 20 units in the AM and 15 units in the PM (total 35 units/day), representing approximately 0.28 units/kg/day based on 125 kg weight 1
• Titrate upward by 4 units every 3 days until fasting glucose reaches 80-130 mg/dL, as the current fasting glucose of 112 mg/dL is acceptable but postprandial control is severely inadequate 1
• Continue aggressive titration until reaching approximately 0.4-0.5 units/kg/day (50-62 units total daily) given the severe hyperglycemia 1
• Critical threshold warning: When basal insulin approaches 0.5 units/kg/day without achieving glycemic targets, prioritize intensifying prandial coverage rather than continuing to escalate basal insulin alone to avoid overbasalization 1

Renal Impairment Considerations

• With GFR 25 mL/min/1.73m² (Stage 4 CKD), insulin clearance is significantly decreased, requiring closer monitoring for hypoglycemia 1
• However, do not reduce the starting dose given the severe hyperglycemia (glucose 400 mg/dL)—the risk of persistent hyperglycemia outweighs hypoglycemia risk at this stage 1
• Monitor glucose levels before each meal and at bedtime during titration 1
• Be prepared to reduce doses by 10-20% immediately if hypoglycemia occurs 1

Prandial Insulin Initiation (Critical Priority)

Blood glucose of 400 mg/dL with meals indicates both inadequate basal coverage AND insufficient mealtime insulin—you must add prandial insulin immediately. 1

Starting Prandial Insulin Dose

• Start with 6-8 units of rapid-acting insulin (Humalog, Novolog, or Apidra) before each meal 1
• Alternative calculation: Use 10% of current basal dose (approximately 2.5 units from 25 units total Lantus), but given the severity of hyperglycemia, start higher at 6-8 units 1
• Administer 0-15 minutes before meals for optimal postprandial control 1
• Titrate prandial doses by 1-2 units every 3 days based on 2-hour postprandial glucose readings, targeting <180 mg/dL 1

Carbohydrate-to-Insulin Ratio Calculation

Initial carb ratio should be approximately 1:10 to 1:12 (1 unit of insulin per 10-12 grams of carbohydrate) 1

• Calculate using the 450 rule: 450 ÷ Total Daily Dose (TDD) 1
• With projected TDD of 50-60 units (35 units basal + 18-24 units prandial), the ratio would be: 450 ÷ 55 = approximately 1:8 1
• Start conservatively at 1:10 given renal impairment, then adjust based on postprandial glucose patterns 1
• For a typical 60-gram carbohydrate meal, this translates to 6 units of rapid-acting insulin 1

Correction Factor (Insulin Sensitivity Factor)

Initial correction factor should be approximately 1:40 (1 unit lowers glucose by 40 mg/dL) 1

• Calculate using the 1500 rule: 1500 ÷ TDD 1
• With TDD of 55 units: 1500 ÷ 55 = approximately 1:27 1
• Start conservatively at 1:40 given renal impairment and increased hypoglycemia risk 1
• Use correction doses for pre-meal glucose >150 mg/dL: (Current glucose - 125) ÷ 40 1

NPH Insulin: Do Not Use

NPH insulin should NOT be added to this regimen—Lantus provides superior basal coverage with significantly lower nocturnal hypoglycemia risk. 2, 3

• NPH has an unpredictable peak at 4-12 hours, increasing hypoglycemia risk, especially problematic with renal impairment 2, 3
• Lantus provides peakless, 24-hour coverage with more stable glucose control 2, 3
• Never mix or overlap two different basal insulins (Lantus and NPH)—this creates unnecessary complexity and dramatically increases hypoglycemia risk 1

Jardiance Management in Renal Impairment

Discontinue Jardiance 10 mg immediately—it is contraindicated and ineffective with GFR <30 mL/min/1.73m². 4, 5

• SGLT2 inhibitors like empagliflozin require adequate renal function for glucose excretion 4, 5
• Urinary glucose excretion decreases dramatically with GFR <30, rendering Jardiance ineffective 5
• Continuing Jardiance provides no glycemic benefit and exposes the patient to unnecessary adverse effects 5

Foundation Therapy: Metformin Optimization

Verify metformin status and optimize dosing if not contraindicated by renal function. 1

• With GFR 25 mL/min/1.73m², metformin is contraindicated per FDA guidelines (requires GFR ≥30) 1
• If patient is currently on metformin, discontinue immediately due to lactic acidosis risk 1
• Focus insulin intensification as primary therapy given renal contraindication to metformin 1

Monitoring Protocol

Daily Glucose Monitoring During Titration

• Check fasting glucose every morning to guide basal insulin titration 1
• Check pre-meal glucose before each meal to calculate correction doses 1
• Check 2-hour postprandial glucose after largest meal to assess prandial insulin adequacy 1
• Check bedtime glucose to ensure overnight safety 1

Titration Schedule

• Adjust basal Lantus every 3 days based on fasting glucose patterns 1
• Adjust prandial insulin every 3 days based on 2-hour postprandial readings 1
• If hypoglycemia occurs, reduce corresponding dose by 10-20% immediately 1

Critical Pitfalls to Avoid

Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day (62-125 units) without adequate prandial coverage—this leads to overbasalization with increased hypoglycemia and suboptimal control 1

Do not delay adding prandial insulin—glucose of 400 mg/dL clearly indicates need for both basal AND mealtime coverage 1

Do not use sliding scale insulin as monotherapy—scheduled basal-bolus regimens are superior and explicitly recommended by all major guidelines 1

Do not give rapid-acting insulin at bedtime—this dramatically increases nocturnal hypoglycemia risk 1

Do not continue Jardiance with GFR <30—it is ineffective and potentially harmful 4, 5

Expected Outcomes

• With proper basal-bolus therapy at weight-based dosing, 68% of patients achieve mean blood glucose <140 mg/dL versus only 38% with inadequate regimens 1
• HbA1c reduction of 2-3% is achievable with appropriate insulin intensification 1
• Fasting glucose should reach 80-130 mg/dL within 2-3 weeks of aggressive titration 1
• Postprandial glucose should improve to <180 mg/dL within 3-4 weeks with prandial insulin optimization 1

Reassessment Timeline

• Every 3 days during active titration to adjust insulin doses 1
• Weekly contact during first month to ensure proper technique and address concerns 1
• Every 3 months once stable to reassess HbA1c and overall glycemic control 1
• Consider adding GLP-1 receptor agonist if basal insulin exceeds 0.5 units/kg/day and HbA1c remains elevated after 3-6 months 1