For a patient with hyperglycemia on 14 units of long-acting (NPH) insulin at bedtime, should the long-acting insulin be increased or a sliding scale insulin regimen be added?

Increase the Long-Acting Insulin Dose

For a patient with persistent hyperglycemia on 14 units of bedtime NPH insulin, the recommended approach is to systematically titrate the basal insulin dose upward by 2 units every 2-3 days until fasting blood glucose targets are achieved, rather than adding sliding scale insulin alone. 1

Why Titrate Basal Insulin First

• Sliding scale insulin (correctional insulin alone without basal coverage) is associated with worse glycemic control and higher rates of perioperative complications compared to basal-bolus regimens in multiple clinical settings 1

• The current NPH dose of 14 units is likely insufficient for this patient's basal insulin requirements, as evidenced by persistent elevated blood sugars 1

• Basal insulin should be titrated to normalize fasting plasma glucose before considering additional prandial or correctional insulin 1

Specific Titration Protocol

Increase the bedtime NPH insulin by 2 units every 2-3 days until fasting blood glucose reaches target range of 90-150 mg/dL (5.0-8.3 mmol/L) 1

• Monitor fasting finger-stick glucose values over each week 1

• If 50% or more of fasting values are above goal: increase dose by 2 units 1

• If more than 2 fasting values per week are below 80 mg/dL (4.4 mmol/L): decrease dose by 2 units 1

• Continue this systematic titration until fasting glucose is controlled 1

When to Add Correctional Insulin

• Correctional (sliding scale) insulin should be added as supplemental coverage, not as the primary strategy 1

• Once basal insulin is optimized but A1C remains above goal, then consider adding prandial insulin with the largest meal or meal with greatest postprandial glucose excursion 1

• A simplified correctional scale can be used temporarily while adjusting basal doses 1:

  • Blood glucose >250 mg/dL: give 2 units of short/rapid-acting insulin
  • Blood glucose >350 mg/dL: give 4 units of short/rapid-acting insulin

Common Pitfalls to Avoid

• Do not rely on sliding scale insulin alone without adequate basal coverage - this approach is associated with inferior outcomes and does not address the underlying basal insulin deficiency 1

• Avoid undertitration of basal insulin - many patients require significantly more than 14 units to achieve adequate basal coverage 1

• Consider timing adjustment - if the patient develops hypoglycemia on bedtime NPH or frequently forgets evening doses, consider switching to morning administration of a long-acting basal analog 1

• Monitor for signs of overbasalization (basal dose >0.5 units/kg/day, elevated bedtime-to-morning differential, hypoglycemia, high variability) which would indicate need for adjunctive therapies rather than further basal increases 1

Assessment of Adequacy

• Assess the adequacy of basal insulin dose at every visit by evaluating fasting glucose trends and looking for clinical signals that additional therapeutic approaches are needed 1

• If A1C remains above goal after optimizing basal insulin, consider adding GLP-1 receptor agonists or proceeding to basal-bolus regimen rather than continuing to escalate basal insulin alone 1