A 74-year-old male with type 2 diabetes on insulin glargine (Lantus) 18 units and prednisone 10 mg who had a blood glucose of 70 mg/dL overnight after drinking apple juice, is now nil per os for bronchitis and received prednisone 10 mg, with a blood glucose of 218 mg/dL two hours later. What should his insulin glargine dose and insulin‑sensitivity factor be?

Lantus Dose and Insulin Sensitivity Factor Recommendation

Given this patient's recent hypoglycemia (BG 70 mg/dL overnight) and current NPO status for bronchoscopy, reduce the Lantus dose to 14-15 units (approximately 20% reduction from 18 units) and hold it until after the procedure if the bronchoscopy is imminent. Once eating resumes, restart at the reduced dose with close monitoring given the prednisone effect.

Rationale for Dose Reduction

This 74-year-old patient experienced nocturnal hypoglycemia on his current regimen, which is a clear signal that 18 units is excessive for his basal insulin needs. The FDA label for Lantus explicitly recommends an 80% dose (20% reduction) when converting from twice-daily NPH to prevent hypoglycemia 11. This same principle applies when reducing doses after hypoglycemia in elderly patients, who are at particularly high risk for severe hypoglycemic events.

Key concern: The patient is now NPO for a procedure. Continuing full-dose basal insulin while NPO significantly increases hypoglycemia risk, especially after a recent episode at 70 mg/dL 1.

Managing the Prednisone Effect

The current BG of 218 mg/dL is likely driven by the 10 mg prednisone dose given 2 hours ago. However, do not increase basal insulin to chase steroid-induced hyperglycemia. Here's why:

• Prednisone causes disproportionate daytime hyperglycemia with relative normalization overnight 23
• The patient already demonstrated nocturnal hypoglycemia on 18 units
• Increasing Lantus would worsen overnight hypoglycemia risk while inadequately covering daytime steroid peaks

Better approach for steroid coverage: Use correctional (sliding scale) rapid-acting insulin every 4-6 hours to address the daytime hyperglycemia from prednisone 2. For patients on once-daily intermediate-acting steroids like prednisone, NPH insulin given with the morning steroid dose is actually preferred over long-acting basal insulin, but since this patient is already on Lantus, aggressive correctional dosing is the practical solution 23.

Insulin Sensitivity Factor (Correction Factor)

For a 74-year-old patient with hypoglycemia risk, use a conservative insulin sensitivity factor of 1 unit per 50-60 mg/dL above target (rather than the standard 1:40-50 for younger patients).

• Target BG for correction: 100-150 mg/dL (more liberal given age and recent hypoglycemia)
• Example: If BG is 250 mg/dL, give 2-3 units of rapid-acting insulin
• Check BG every 4 hours while NPO and receiving steroids 2

The 2023 ADA guidelines emphasize that elderly patients with hypoglycemia risk should have reduced starting doses (0.15 U/kg per day for basal alone) 4. This patient's recent hypoglycemia places him squarely in this high-risk category.

Critical Pitfalls to Avoid

1. Never hold all basal insulin in type 2 diabetes patients on chronic insulin therapy - even while NPO, some basal coverage is needed. The 20% reduction balances hypoglycemia risk with maintaining basal coverage 11

2. Don't increase Lantus to treat steroid hyperglycemia - this creates nocturnal hypoglycemia. Studies show that increasing basal insulin for steroids leads to worse overnight glucose control 35

3. Monitor closely during NPO period - check BG every 4 hours minimum. If BG drops below 100 mg/dL while NPO, start D10W infusion 2

4. Age matters - at 74 years old, this patient has higher morbidity/mortality risk from hypoglycemia than from transient hyperglycemia 67. A study specifically in patients ≥65 years showed that conservative dosing with lower hypoglycemia risk is paramount 6

Post-Procedure Plan

Once the patient resumes eating after bronchoscopy:

• Restart Lantus at 14-15 units daily
• Add rapid-acting insulin before meals (start conservatively at 4 units per meal if eating full meals)
• Continue correctional insulin with the 1:50-60 sensitivity factor
• If prednisone continues, expect to need 40-60% more prandial insulin during the day 2
• Recheck dosing daily based on glucose patterns

The recent hypoglycemia episode is the most important clinical data point here - it supersedes the current steroid-induced hyperglycemia in determining safe basal insulin dosing 8.