What is the initial insulin prescription for a patient with type 2 Diabetes Mellitus (DM) and an Hemoglobin A1c (HbA1c) of 10%?

How to Prescribe Insulin in Type 2 Diabetes with HbA1c 10%

Initial Insulin Prescription

Start basal insulin at 10 units once daily OR 0.1-0.2 units/kg body weight once daily, administered subcutaneously at the same time each day, in conjunction with metformin. 1

Step-by-Step Initiation Protocol

Starting Dose Selection

• For most patients: Begin with 10 units of basal insulin (glargine, detemir, or degludec) once daily 1
• For patients with significant hyperglycemia or higher body weight: Use 0.1-0.2 units/kg/day as the starting dose 1
• Timing: Administer at any consistent time of day (bedtime is common), but the same time every 24 hours 2

Concurrent Medication Management

• Continue metformin at current dose—this is essential and should not be discontinued 1
• Consider adding one additional non-insulin agent (such as an SGLT2 inhibitor or GLP-1 receptor agonist) for complementary mechanisms 1
• Discontinue sulfonylureas if moving beyond simple basal insulin to avoid excessive hypoglycemia risk 1

Dose Titration Algorithm

Increase basal insulin by 2-4 units (or 10-15% of current dose) once or twice weekly until fasting blood glucose reaches target of 80-130 mg/dL (4.4-7.2 mmol/L). 1

• Base adjustments on the mean of 3 consecutive fasting blood glucose readings 1, 3
• If fasting glucose ≥180 mg/dL (≥10 mmol/L): increase by 6-8 units 3
• If fasting glucose 140-180 mg/dL (7.8-10 mmol/L): increase by 4 units 3
• If fasting glucose 120-140 mg/dL (6.7-7.8 mmol/L): increase by 2 units 3
• If fasting glucose 100-120 mg/dL (5.6-6.7 mmol/L): increase by 0-2 units 3
• Hold increases if any blood glucose <72 mg/dL (<4.0 mmol/L) 1, 3

When Basal Insulin Alone Is Insufficient

Indications for Intensification

If after optimizing basal insulin (dose >0.5 units/kg/day OR fasting glucose at target) the HbA1c remains >7%, advance therapy by: 1

Adding Prandial Insulin

• Start with 4 units of rapid-acting insulin (aspart, lispro, or glulisine) before the largest meal 1
• Alternative dosing: 0.1 units/kg per meal OR 10% of basal insulin dose per meal 1
• If HbA1c <8% when adding prandial insulin, reduce basal insulin dose by 4 units or 10% to prevent hypoglycemia 1
• Titrate prandial doses by 1-2 units twice weekly based on 2-hour postprandial glucose readings 1, 4

Alternative: Premixed Insulin

• Consider twice-daily premixed insulin (70/30 NPH/Regular) for patients who prefer simpler dosing 1
• Caveat: Requires relatively fixed meal schedule and carbohydrate content 1
• Less flexible than basal-bolus regimens 1

Special Considerations for HbA1c 10%

High Baseline HbA1c Context

• At HbA1c 10%, dual therapy initiation may be appropriate to achieve more rapid glycemic control 1, 4
• Consider starting basal insulin PLUS a GLP-1 receptor agonist simultaneously, as this combination can reduce HbA1c by 2-2.5% with weight loss benefits 4, 5
• Avoid prolonged severe hyperglycemia (months at HbA1c >9%) due to increased complication risk 4

Cost Considerations

• Long-acting basal analogs (glargine, detemir, degludec) cause less hypoglycemia than NPH insulin 1
• However, NPH insulin may be more affordable for some patients and remains a reasonable option 1
• Substantial insulin price increases over the past decade make cost-effectiveness an important consideration 1

Critical Patient Education Requirements

Before Starting Insulin

• Self-monitoring of blood glucose: Teach proper technique and frequency (at minimum, fasting glucose daily during titration) 1
• Hypoglycemia recognition and treatment: Symptoms, glucose <70 mg/dL, treatment with 15g fast-acting carbohydrate 1
• Injection technique: Subcutaneous administration into abdomen, thigh, or deltoid with site rotation 2
• Insulin is NOT a punishment or sign of failure—emphasize the progressive nature of type 2 diabetes 1

Self-Titration Empowerment

• Providing patients with a self-titration algorithm improves glycemic control compared to clinic-managed titration alone 1, 3
• Patient-managed titration (increase by 2 units every 3 days if fasting glucose >100 mg/dL and no hypoglycemia) achieved greater HbA1c reduction than clinic-managed approaches 3

Common Pitfalls to Avoid

Clinical Inertia

• Do NOT delay insulin initiation in patients not achieving glycemic goals with oral agents 1, 4
• Delaying insulin intensification for months while trying additional oral agents prolongs exposure to severe hyperglycemia 4

Inadequate Titration

• Timely dose titration is essential—many patients remain on subtherapeutic doses for too long 1, 6
• Reassess every 2-3 months and adjust if HbA1c not at target 4, 6

Sliding Scale Monotherapy

• Never rely solely on sliding scale (correction) insulin without basal insulin—this approach is ineffective for long-term management 4

Lipodystrophy Risk

• Rotate injection sites within the same region to reduce risk of lipodystrophy and localized cutaneous amyloidosis 2
• Repeated injections into areas of lipodystrophy can cause hyperglycemia; sudden change to unaffected areas can cause hypoglycemia 2

Hypoglycemia Monitoring

• Increase blood glucose monitoring frequency during any insulin regimen changes 2
• Ensure glucagon availability and educate on its use 4
• Consider continuous glucose monitoring to identify patterns and reduce hypoglycemia risk 4

Monitoring and Follow-Up

Short-Term (Weeks 1-12)

• Check fasting blood glucose daily during titration phase 1, 3
• Adjust insulin dose weekly or twice-weekly based on glucose patterns 1
• Monitor for hypoglycemia, especially 2-4 hours after rapid-acting insulin if using prandial coverage 4

Medium-Term (3 Months)

• Measure HbA1c after 3 months to assess treatment effectiveness 4, 6
• If HbA1c remains >8% on optimized basal insulin, add prandial insulin or GLP-1 receptor agonist 1, 4

Long-Term Considerations

• Monitor for weight gain associated with insulin therapy 4
• Reassess cardiovascular risk factors and consider agents with cardiovascular benefits (GLP-1 receptor agonists, SGLT2 inhibitors) 1, 4
• Evaluate renal function periodically as this affects medication choices 1