What is the best approach to taper a 90-year-old patient with type 2 diabetes off insulin and control their blood sugar levels with anti-hyperglycemic agents, specifically oral hypoglycemic agents (OHAs), while already on metformin (Metformin) 500 milligrams per oral (PO) twice a day (BID)?

Tapering Insulin in a 90-Year-Old with Type 2 Diabetes

The best approach to taper a 90-year-old patient with type 2 diabetes off insulin is to follow the American Diabetes Association's algorithm for insulin simplification, which includes gradually reducing insulin while adding non-insulin agents, with careful monitoring of blood glucose levels every 2 weeks. 1

Initial Assessment and Goals

• For a 90-year-old patient, set a more relaxed glycemic target:
  • Fasting glucose goal: 90-150 mg/dL (5.0-8.3 mmol/L)
  • A1C goal: <8.0% for patients with complex health status 1
• Evaluate current insulin regimen (basal, prandial, or premixed)
• Assess renal function (eGFR) to guide medication choices

Step-by-Step Insulin Tapering Protocol

For Patients on Basal Insulin:

1. Change timing from bedtime to morning administration
2. Titrate basal insulin based on fasting glucose readings over a week:
   • If 50% of fasting values are above goal: Increase by 2 units
   • If >2 fasting values/week are <80 mg/dL: Decrease by 2 units

For Patients on Prandial Insulin:

1. If mealtime insulin ≤10 units/dose: Discontinue prandial insulin and add non-insulin agent
2. If prandial insulin >10 units/dose: Decrease dose by 50% and add non-insulin agent
3. Gradually titrate prandial insulin doses down as non-insulin agents are increased

For Patients on Premixed Insulin:

1. Use 70% of total dose as basal only in the morning
2. Follow same principles as above for adjusting doses 1

Adding Non-Insulin Agents

The patient is already on metformin 500 mg BID, which is appropriate as first-line therapy. Consider:

1. Optimize current metformin therapy:

   • If tolerated and eGFR ≥45 mL/min/1.73m², can increase to target dose of 2000 mg/day 2
   • Consider extended-release formulation if GI side effects occur 3

2. Add second-line agents based on patient characteristics:

   • DPP-4 inhibitors: Minimal hypoglycemia risk, well-tolerated in elderly 1
   • SGLT-2 inhibitors: Consider if cardiovascular or renal benefits desired
   • GLP-1 receptor agonists: Effective but consider injection requirements and potential GI side effects 4

Monitoring and Adjustment Schedule

1. Monitor fasting glucose levels daily for the first 2 weeks
2. Adjust insulin dose every 2 weeks based on glucose patterns
3. Check pre-meal glucose levels before lunch and dinner
4. Re-evaluate every 2-4 weeks until stable on oral agents 1

Special Considerations for the Elderly

• Hypoglycemia risk: Prioritize agents with low hypoglycemia risk (metformin, DPP-4 inhibitors)
• Polypharmacy: Simplify regimen when possible to improve adherence
• Renal function: Adjust medication doses based on eGFR
• Cognitive function: Ensure patient can manage medication regimen or has adequate support

Common Pitfalls to Avoid

• Too rapid insulin reduction: Can lead to hyperglycemia and symptoms
• Inadequate monitoring: Increases risk of both hyper- and hypoglycemia
• Ignoring renal function: Many agents require dose adjustment or are contraindicated with reduced renal function
• Overlooking hypoglycemia risk: Especially dangerous in elderly patients
• Not adding appropriate non-insulin agents: May result in poor glycemic control after insulin reduction

By following this structured approach with careful monitoring and gradual adjustments, most 90-year-old patients can be successfully transitioned from insulin to oral antihyperglycemic agents while maintaining adequate glycemic control and reducing hypoglycemia risk.