Initial Insulin Dosing for a 275-Pound Patient with Type 2 Diabetes
For a 275-pound (125 kg) patient with type 2 diabetes who is insulin-naive, start with basal insulin at 10 units once daily OR 0.1-0.2 units/kg/day (12-25 units), administered at the same time each day. 1
Weight-Based Calculation
For this 275-pound patient (125 kg):
- Conservative starting dose: 0.1 units/kg = 12-13 units once daily 1
- Standard starting dose: 0.2 units/kg = 25 units once daily 1
- Alternative fixed dose: 10 units once daily regardless of weight 1, 2
The American Diabetes Association recommends choosing between these approaches based on the degree of hyperglycemia present 1. If HbA1c is ≥9% or blood glucose is ≥300-350 mg/dL, use the higher end of the range (0.2 units/kg = 25 units) or consider starting at 0.3-0.5 units/kg/day (37-62 units) as total daily insulin with a basal-bolus regimen from the outset. 1
Titration Protocol
Increase the basal insulin dose every 3 days based on fasting glucose patterns: 1, 2
- If fasting glucose is 140-179 mg/dL: increase by 2 units every 3 days 1
- If fasting glucose is ≥180 mg/dL: increase by 4 units every 3 days 1
- Target fasting glucose: 80-130 mg/dL 1
- If hypoglycemia occurs without clear cause, reduce dose by 10-20% immediately 1, 3
Foundation Therapy
Continue metformin unless contraindicated when starting insulin therapy, as this combination reduces total insulin requirements, limits weight gain, and improves glycemic control compared to insulin alone. 1, 2, 4 Consider continuing one additional non-insulin agent as well. 1
Critical Threshold: When to Stop Escalating Basal Insulin
When basal insulin exceeds 0.5 units/kg/day (62 units for this patient) and approaches 1.0 units/kg/day (125 units), adding prandial insulin or a GLP-1 receptor agonist becomes more appropriate than continuing to escalate basal insulin alone. 1, 3, 5 Clinical signals of "overbasalization" include: 1
- Basal dose >0.5 units/kg/day
- Bedtime-to-morning glucose differential ≥50 mg/dL
- Hypoglycemia episodes
- High glucose variability
Adding Prandial Insulin (If Needed)
If after 3-6 months of basal insulin optimization, fasting glucose reaches target but HbA1c remains above goal, start prandial insulin with 4 units of rapid-acting insulin before the largest meal OR use 10% of the current basal dose. 1 Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings. 1
Monitoring Requirements
- Daily fasting blood glucose monitoring is essential during titration 1, 2
- Reassess adequacy of insulin dose at every clinical visit 1
- Check HbA1c every 3 months during intensive titration 1
Common Pitfalls to Avoid
- Never delay insulin initiation in patients not achieving glycemic goals with oral medications, as this prolongs hyperglycemia exposure and increases complication risk 1
- Never discontinue metformin when starting insulin unless contraindicated, as this leads to higher insulin requirements and more weight gain 1, 2
- Never continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to overbasalization with increased hypoglycemia risk and suboptimal control 1, 5