What is the recommended insulin regimen for a 78‑year‑old man with type 2 diabetes on 5 U daily insulin glargine (Lantus) basal and sliding‑scale correction, whose glucose ranges from 109 mg/dL to 307 mg/dL?

Aggressive Insulin Intensification Required for Severe Uncontrolled Hyperglycemia

This 78-year-old patient with blood glucose ranging 109–307 mg/dL on only 5 units of Lantus daily plus sliding-scale insulin requires immediate basal insulin escalation and addition of scheduled prandial insulin; the current regimen is profoundly inadequate and sliding-scale monotherapy must be discontinued.

Critical Problems with Current Regimen

• Sliding-scale insulin as monotherapy is explicitly condemned by all major diabetes guidelines and achieves target glucose (<140 mg/dL) in only 38% of patients versus 68% with scheduled basal-bolus therapy 1, 2.
• A basal dose of only 5 units daily is grossly insufficient for any adult with type 2 diabetes experiencing glucose values exceeding 300 mg/dL 1.
• Blood glucose in the 300s represents complete therapeutic failure requiring immediate intervention to prevent acute and long-term complications 1, 3.

Immediate Insulin Regimen Changes

Basal Insulin (Lantus) Escalation

• Increase Lantus to at least 0.2–0.3 units/kg/day as the starting basal dose for severe hyperglycemia 1, 4.
• For a typical 70–80 kg older adult, this translates to 14–24 units once daily at the same time each day 1, 4.
• Titrate basal insulin aggressively by 4 units every 3 days when fasting glucose remains ≥180 mg/dL until reaching target fasting glucose of 80–130 mg/dL 1.
• If fasting glucose is 140–179 mg/dL, increase by 2 units every 3 days 1.

Addition of Prandial Insulin Coverage

• Start rapid-acting insulin (lispro, aspart, or glulisine) at 4 units before each of the three largest meals (or 10% of the basal dose) 1.
• Administer prandial insulin 0–15 minutes before meals for optimal postprandial control 1.
• Titrate each meal dose by 1–2 units every 3 days based on 2-hour postprandial glucose readings, targeting <180 mg/dL 1.

Correction Insulin Protocol (Adjunct Only)

• Add 2 units of rapid-acting insulin for pre-meal glucose >250 mg/dL and 4 units for glucose >350 mg/dL, in addition to scheduled prandial doses 1.
• Never use correction insulin as the sole treatment—it must supplement a scheduled basal-bolus regimen 1, 2.

Foundation Oral Therapy

• Continue or initiate metformin at maximum tolerated dose (up to 2000–2550 mg daily) unless contraindicated by renal impairment or other factors 1, 5.
• Metformin combined with insulin reduces total insulin requirements by 20–30% and provides superior glycemic control versus insulin alone 1, 5.
• Discontinue sulfonylureas when advancing to basal-bolus insulin to prevent additive hypoglycemia risk 1.

Critical Threshold Monitoring

• When basal insulin approaches 0.5–1.0 units/kg/day (35–80 units for a 70–80 kg patient) without achieving targets, intensify prandial insulin rather than continuing basal escalation to avoid "over-basalization" with increased hypoglycemia risk 1.
• Clinical signals of over-basalization include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia episodes, and high glucose variability 1.

Glucose Monitoring Requirements

• Check fasting glucose daily to guide basal insulin titration 1.
• Check pre-meal glucose before each meal to calculate correction doses 1.
• Check 2-hour postprandial glucose to assess adequacy of prandial insulin coverage 1.
• During active titration, monitor at least 4 times daily (fasting, pre-meals, bedtime) 1.

Expected Clinical Outcomes

• With appropriate basal-bolus therapy at weight-based dosing, 68% of patients achieve mean glucose <140 mg/dL compared with only 38% using sliding-scale alone 1, 2.
• No increase in hypoglycemia incidence when basal-bolus regimens are properly implemented versus inadequate sliding-scale approaches 1, 2.
• Anticipated HbA1c reduction of 2–3% over 3–6 months with intensive insulin titration 1.

Hypoglycemia Management

• Treat any glucose <70 mg/dL immediately with 15 grams of fast-acting carbohydrate, recheck in 15 minutes, and repeat if needed 1.
• If hypoglycemia occurs without clear cause, reduce the implicated insulin dose by 10–20% immediately 1, 4.

Common Pitfalls to Avoid

• Never continue sliding-scale insulin as monotherapy—evidence definitively shows it is inferior and unsafe 1, 2.
• Never delay addition of prandial insulin when blood glucose consistently exceeds 250 mg/dL 1.
• Never discontinue metformin when starting insulin unless medically contraindicated 1, 5.
• Never give rapid-acting insulin solely at bedtime as a correction dose, as this markedly increases nocturnal hypoglycemia risk 1.
• Never continue escalating basal insulin beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia through prandial insulin 1.

Special Considerations for Older Adults

• For patients >65 years with multiple comorbidities, consider a slightly less aggressive HbA1c target of <8.0% rather than <7.0% 1.
• Use lower starting doses (0.1–0.25 units/kg/day) in frail elderly patients with renal impairment or poor oral intake to reduce hypoglycemia risk 1.
• However, this patient's glucose values in the 300s still mandate aggressive intervention regardless of age 1, 3.

Follow-Up Schedule

• Reassess every 3 days during active titration to adjust insulin doses 1.
• Reassess every 3–6 months once stable to evaluate overall glycemic control and HbA1c 1.
• Consider endocrinology referral if unable to achieve targets or if HbA1c remains >9% despite optimization 1.