What is the best strategy to transition a patient with type 1 diabetes from an insulin pump to subcutaneous insulin?

Transitioning from Insulin Pump to Subcutaneous Insulin

When Transition is Necessary

Professional societies advocate for continuation of insulin pump therapy in appropriate hospitalized patients, but in the absence of key elements (hospital policies, trained staff, patient ability to self-manage), the alternative is to switch to basal-bolus insulin therapy. 1

Absolute contraindications requiring immediate transition include: 1

• Impaired level of consciousness (except during short-term anesthesia)
• Patient's inability to correctly use pump settings or self-manage diabetes
• Hyperglycemic crises (DKA/HHS)
• Lack of pump supplies or trained healthcare providers
• Certain radiological procedures (MRI, diathermy)
• Software problems, alarm errors, site infection, or cybersecurity concerns

Calculating the Subcutaneous Insulin Dose

Step 1: Determine Total Daily Dose from Pump Settings

The dose of long-acting basal insulin is derived from the 24-hour total basal dose from the insulin pump settings. 1

• Review the pump's basal rate settings over 24 hours and sum all hourly rates to get total basal insulin 1
• For type 1 diabetes, basal insulin typically represents 40-60% of total daily dose (TDD) 1
• Total basal dose = approximately 0.48 × TDD (or 30-50% of TDD) 2

Step 2: Calculate Basal and Prandial Components

Use a 50:50 split between basal and prandial insulin when transitioning to multiple daily injections. 1, 2

For the basal component: 1

• Give 100% of the pump's 24-hour basal rate as long-acting insulin (glargine or detemir) once daily
• Administer this dose at the same time each day

For the prandial component: 2

• Calculate the remaining 50% of TDD and divide equally among three meals as rapid-acting insulin
• Use the pump's insulin-to-carbohydrate ratios (typically 1:10 to 1:15) to guide meal dosing 2
• Calculate correction factor as 1500 ÷ TDD for adjusting pre-meal hyperglycemia 2

Critical Timing Considerations

Administer the first dose of long-acting basal insulin 2-4 hours before discontinuing the insulin pump to ensure adequate plasma insulin levels and prevent hyperglycemia. 3

• Continue pump therapy for 1-2 hours after giving subcutaneous basal insulin 3
• This overlap prevents gaps in insulin coverage that could precipitate hyperglycemia or ketosis 3

Special Situations Requiring Dose Adjustment

For Hospitalized Patients

Reduce the home insulin dose by 20% when admitting patients on high-dose insulin (≥0.6 units/kg/day) to prevent hypoglycemia. 2, 4

For high-risk populations (elderly >65 years, renal failure, poor oral intake): 2, 4

• Use lower starting doses of 0.1-0.25 units/kg/day
• Monitor glucose every 4-6 hours if oral intake is poor 4

For Patients with Renal Impairment

Patients with CKD Stage 5 and type 1 diabetes should reduce their total daily insulin dose by 35-40%. 2

• Monitor closely for hypoglycemia as insulin clearance decreases with declining kidney function 2
• Titrate conservatively in patients with eGFR <45 mL/min/1.73 m² 2

Monitoring and Titration Protocol

Initial Monitoring

Check blood glucose every 2-4 hours for the first 24-48 hours after transitioning from pump to subcutaneous insulin. 3

Target ranges: 4, 3

• Premeal glucose: 80-130 mg/dL (or 90-150 mg/dL for some protocols)
• Random/postprandial glucose: <180 mg/dL
• Fasting glucose: 80-130 mg/dL

Basal Insulin Titration

Adjust basal insulin every 3 days based on fasting glucose patterns. 2

• If fasting glucose 140-179 mg/dL: increase by 2 units every 3 days 2
• If fasting glucose ≥180 mg/dL: increase by 4 units every 3 days 2
• If hypoglycemia occurs without clear cause: reduce dose by 10-20% immediately 2

Prandial Insulin Titration

Adjust prandial insulin by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings. 2

• Target postprandial glucose <180 mg/dL 4
• Use correction insulin for premeal glucose >180 mg/dL 4

Critical Pitfalls to Avoid

Never stop the insulin pump without prior administration of subcutaneous basal insulin, as this creates a dangerous gap in insulin coverage that can precipitate hyperglycemia or DKA in type 1 diabetes patients. 3

Additional pitfalls: 1, 4

• Do not use sliding scale insulin alone as the sole regimen—it results in poorer glycemic control and increased complications
• Do not give rapid-acting insulin at bedtime, as this significantly increases nocturnal hypoglycemia risk
• Do not use premixed insulin formulations in the hospital setting—they cause threefold higher hypoglycemia rates
• Do not forget that type 1 diabetes patients must receive basal insulin even when NPO

Patient Education Requirements

Before discharge, ensure patients understand: 2

• Proper insulin injection technique and site rotation
• Recognition and treatment of hypoglycemia (15 grams fast-acting carbohydrate for glucose ≤70 mg/dL)
• Self-monitoring of blood glucose
• "Sick day" management rules
• Insulin storage and handling

When to Consider Returning to Pump Therapy

Hospital policies should ideally incorporate guidance on transitioning a patient from subcutaneous insulin back to their pump if applicable, particularly once the patient is stable, able to self-manage, and the contraindications have resolved. 1