How should I recalculate the insulin dose or adjust therapy for an adult patient with type 2 diabetes who is non‑compliant, currently on premixed insulin 70/30 with a sliding‑scale order, and now has hyperglycemia (random glucose 260 mg/dL)?

Transition from Premixed Insulin 70/30 to Basal-Bolus Therapy for Uncontrolled Type 2 Diabetes

Immediately discontinue insulin 70/30 and switch to a basal-bolus regimen using insulin glargine plus rapid-acting insulin before meals, as premixed insulin 70/30 carries unacceptably high hypoglycemia risk and lacks the flexibility needed for adequate glycemic control in this patient. 1

Why Insulin 70/30 Has Failed

Your patient's random glucose of 260 mg/dL despite insulin 70/30 therapy reflects the fundamental limitations of premixed insulin formulations:

• The fixed 70:30 ratio cannot be independently adjusted to address both fasting hyperglycemia and postprandial excursions, forcing you to choose between undertreating one component or overtreating the other. 2
• Premixed insulin 70/30 is explicitly contraindicated in hospital settings due to unacceptably high iatrogenic hypoglycemia rates (64% vs. 24% with basal-bolus therapy in randomized trials), and this same risk extends to outpatient management. 1, 2
• Non-compliance compounds the problem because missed doses of premixed insulin create dangerous glucose fluctuations, whereas basal-bolus therapy allows you to address adherence issues separately for basal versus prandial components. 2

Immediate Medication Changes Required

Calculate Total Daily Insulin Dose

• Estimate current total daily insulin requirement at 0.3–0.5 units/kg/day given the severe hyperglycemia (random glucose 260 mg/dL indicates both inadequate basal and prandial coverage). 1
• For a typical adult weighing 70 kg, this translates to approximately 21–35 units/day total. 1

Basal Insulin (Insulin Glargine)

• Start insulin glargine at 50% of the calculated total daily dose (approximately 11–18 units once daily at bedtime). 1, 2
• Titrate by 4 units every 3 days if fasting glucose remains ≥180 mg/dL; increase by 2 units every 3 days if fasting glucose is 140–179 mg/dL. 1
• Target fasting glucose 80–130 mg/dL. 1
• Stop basal escalation when the dose approaches 0.5 units/kg/day (approximately 35 units for a 70 kg patient) without achieving targets; at this threshold, intensify prandial insulin rather than continuing basal increases. 1

Prandial Insulin (Rapid-Acting)

• Allocate the remaining 50% of total daily dose to rapid-acting insulin (lispro, aspart, or glulisine) divided among three meals—approximately 4–6 units before breakfast, lunch, and dinner. 1, 2
• Administer 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

• 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
• Correction insulin must supplement—not replace—scheduled basal and prandial doses; sliding-scale insulin as monotherapy is condemned by all major diabetes guidelines. 1

Addressing Non-Compliance

The basal-bolus regimen offers critical advantages for non-compliant patients:

• Basal insulin glargine provides 24-hour coverage even if prandial doses are missed, preventing the dangerous glucose spikes that occur when premixed insulin doses are skipped. 1
• Missed prandial doses affect only that specific meal, whereas missed premixed insulin doses disrupt both basal and prandial coverage simultaneously. 2
• You can prioritize adherence to basal insulin (one injection daily) while working on prandial compliance separately, rather than requiring perfect adherence to a rigid twice-daily premixed schedule. 2

Metformin Optimization

• Continue or maximize metformin to 2000 mg daily (1000 mg twice daily with meals) unless contraindicated. 1
• Metformin reduces total insulin requirements by 20–30% and provides superior glycemic control when combined with insulin compared to insulin alone. 1
• Never discontinue metformin when intensifying insulin therapy unless specific contraindications exist (renal impairment, acute illness, tissue hypoxia). 1

Monitoring Requirements

• Daily fasting glucose checks to guide basal insulin titration. 1
• Pre-meal glucose before each meal to calculate correction doses. 1
• 2-hour postprandial glucose after each meal to assess prandial insulin adequacy. 1
• Reassess insulin doses every 3 days during active titration. 1
• HbA1c every 3 months until stable control is achieved. 1

Expected Clinical Outcomes

• Approximately 68% of patients achieve mean glucose <140 mg/dL with basal-bolus therapy, compared to only 38% with sliding-scale insulin alone. 1
• HbA1c reduction of 2–3% is achievable within 3–6 months with proper basal-bolus titration. 1
• Randomized trials demonstrate basal-bolus therapy provides superior glycemic control and reduces hospital complications compared to premixed insulin regimens. 1, 2
• Properly implemented basal-bolus regimens do not increase overall hypoglycemia incidence compared to inadequate premixed insulin approaches. 1

Critical Pitfalls to Avoid

• Never convert from premixed insulin to glargine on a 1:1 basis; you must recalculate the total daily insulin dose and redistribute appropriately between basal and prandial components. 2
• Do not mix insulin glargine with any other insulin in the same syringe due to its low pH diluent. 2
• Avoid administering glargine at the same time as prandial insulin to prevent insulin stacking. 2
• Do not continue escalating basal insulin beyond 0.5–1.0 units/kg/day without addressing postprandial hyperglycemia; this leads to "over-basalization" with increased hypoglycemia risk and suboptimal control. 1
• Never rely solely on correction doses without adjusting scheduled basal and prandial insulin; this reactive approach is condemned by major diabetes guidelines. 1

Hypoglycemia Management

• Treat any glucose <70 mg/dL immediately with 15 g of fast-acting carbohydrate (glucose tablets or juice), recheck in 15 minutes, and repeat if needed. 1
• If hypoglycemia occurs without an obvious cause, reduce the implicated insulin dose by 10–20% immediately. 1

Alternative: Consider GLP-1 Receptor Agonist Before Prandial Insulin

• If basal insulin exceeds 0.5 units/kg/day without achieving targets, strongly consider adding a GLP-1 receptor agonist (e.g., semaglutide) instead of prandial insulin. 2
• This combination provides comparable postprandial control with less hypoglycemia and weight loss rather than weight gain. 2

Patient Education Essentials

• Teach proper injection technique and site rotation to prevent lipohypertrophy. 1
• Reinforce hypoglycemia recognition and treatment (symptoms, <70 mg/dL threshold, 15-g carbohydrate rule). 1
• Provide sick-day management instructions: continue insulin even if not eating, check glucose every 4 hours, maintain hydration. 1
• Emphasize that basal insulin must be taken daily even if meals are skipped, to prevent dangerous hyperglycemia and ketosis. 1