How should I adjust the insulin regimen for a patient with Diabetes Mellitus (DM) on insulin glargine (glargine) 20 units in the morning and 15 units at night, and insulin lispro (lispro) 20 units three times a day (TID) at meal times, with a Hemoglobin A1C (HbA1C) level of 11%?

Insulin Regimen Adjustment for Poorly Controlled Diabetes

For a patient with diabetes mellitus on insulin glargine 20 units in the morning and 15 units at night, plus insulin lispro 20 units TID with meals and sliding scale insulin before meals, with an A1C of 11%, the insulin regimen should be optimized by increasing the basal insulin dose and adjusting the prandial insulin doses according to a systematic titration protocol.

Assessment of Current Regimen

• The patient's A1C of 11% indicates severely uncontrolled diabetes, suggesting the current insulin regimen is inadequate despite using both basal (glargine) and bolus (lispro) insulins 1
• The current total daily basal insulin dose is 35 units (20 units morning + 15 units night), which may be insufficient given the high A1C 1
• The fixed prandial insulin dose of 20 units TID may not be appropriately matched to carbohydrate intake and pre-meal glucose levels 1, 2

Basal Insulin Adjustment

• Increase the total basal insulin (glargine) dose by 10-20% to improve fasting glucose control 1
• Adjust the morning dose to 24 units and the evening dose to 18 units (approximately 20% increase) 1, 2
• Set a fasting plasma glucose target and titrate the evening dose by 2 units every 3 days until reaching target without hypoglycemia 1
• Monitor for hypoglycemia; if it occurs, determine the cause and reduce the corresponding dose by 10-20% 1

Prandial Insulin Adjustment

• Increase the prandial insulin (lispro) doses based on pre-meal glucose readings and carbohydrate content of meals 1, 2
• Start with increasing each pre-meal lispro dose to 25 units (approximately 25% increase) 1
• Further titrate each mealtime dose by 1-2 units or 10-15% twice weekly based on 2-hour post-meal glucose values 1
• Target post-meal glucose values of <180 mg/dL 1, 2

Monitoring and Further Adjustments

• Increase the frequency of blood glucose monitoring during insulin dose adjustments 3
• Check blood glucose before meals, 2 hours after meals, and at bedtime to identify patterns 2
• Assess for adequacy of basal insulin by evaluating overnight and fasting glucose trends 1
• Consider clinical signals of overbasalization (basal dose >0.5 units/kg/day, elevated bedtime-morning glucose differential, hypoglycemia) 1

Additional Considerations

• If glycemic targets are not achieved after optimizing basal-bolus insulin, consider adding a GLP-1 receptor agonist, which can improve glycemic control while potentially reducing insulin requirements 1, 4
• Ensure the patient is receiving comprehensive diabetes self-management education to improve adherence and self-care behaviors 2
• Evaluate for potential insulin administration technique issues, such as lipohypertrophy at injection sites 2
• Check A1C every 3 months until target is achieved 2

Common Pitfalls and Caveats

• Avoid excessive increases in insulin doses at one time, which can lead to hypoglycemia 1, 2
• Do not overlook the importance of consistent carbohydrate counting and meal timing when adjusting insulin doses 1, 2
• Remember that insulin requirements may change with physical activity, illness, or changes in body weight 3
• Consider prescription of glucagon for emergent hypoglycemia, especially when increasing insulin doses 1
• Be aware that insulin glargine should not be mixed with other insulins in the same syringe 3

By following this systematic approach to insulin adjustment, the patient's glycemic control should improve significantly, with the goal of reducing A1C to target levels while minimizing the risk of hypoglycemia.