What is the initial insulin dosing regimen for non-insulin dependent (Type 2) diabetes mellitus patients requiring insulin in an inpatient setting?

Initial Insulin Dosing for Non-Insulin Dependent (Type 2) Diabetes Patients in the Inpatient Setting

For insulin-naive Type 2 diabetes patients requiring insulin in the hospital, start with a total daily dose of 0.3-0.5 U/kg/day, with half given as basal insulin (once or twice daily) and half as rapid-acting insulin divided before three meals, using lower doses (0.3 U/kg/day) for patients at higher risk of hypoglycemia including those over 65 years, with renal failure, or poor oral intake. 1

Choosing the Initial Insulin Regimen

For Patients with Good Oral Intake

A basal-bolus regimen is the preferred approach for non-critically ill hospitalized Type 2 diabetes patients with good nutritional intake 1. This approach has demonstrated:

• Superior glycemic control compared to sliding scale insulin alone 1
• Reduction in postoperative complications including wound infection, pneumonia, bacteremia, and acute renal and respiratory failure 1
• Better outcomes than reactive insulin regimens in general surgery patients 1

The basal-bolus regimen consists of:

• Basal insulin (glargine, detemir, or degludec) given once or twice daily 1
• Rapid-acting insulin (lispro, aspart, or glulisine) given before each meal 1
• Correction doses of rapid-acting insulin for hyperglycemia 1

For Patients with Poor or Uncertain Oral Intake

A basal-plus approach is preferred for patients with mild hyperglycemia (blood glucose <11.1 mmol/L or 200 mg/dL), decreased oral intake, or those undergoing surgery 1. This regimen includes:

• Basal insulin at 0.1-0.25 U/kg/day 1
• Correction doses of rapid-acting insulin before meals or every 6 hours if nil by mouth 1

For Patients Who Are Fasting

Use basal insulin with correction doses only for patients who are fasting or expected to undergo procedures 1. Sliding scale insulin alone may be considered for patients without diabetes or those with good metabolic control on oral agents at home, but basal insulin should be added if glucose levels cannot be maintained below 10.0 mmol/L (180 mg/dL) 1.

Specific Dosing Calculations

For Insulin-Naive Patients

Starting dose: 0.3-0.5 U/kg/day total daily insulin 1

Distribution:

• 50% as basal insulin (given 1-2 times daily) 1
• 50% as rapid-acting insulin (divided equally before three meals) 1

Example for a 70 kg patient:

• Total daily dose: 21-35 units
• Basal insulin: 10-17 units once or twice daily
• Rapid-acting insulin: 3-6 units before each meal

For High-Risk Patients (Use Lower End of Dosing Range)

Start at 0.3 U/kg/day for: 1

• Patients over 65 years of age
• Those with renal failure
• Those with poor oral intake

For Patients Already on Insulin at Home

If taking ≥0.6 U/kg/day at home: Reduce total daily insulin dose by 20% while hospitalized to prevent hypoglycemia in the setting of poor oral intake 1

Insulin Timing and Administration

For eating patients:

• Administer rapid-acting insulin immediately before meals 1
• Perform point-of-care glucose testing immediately before meals 1

If oral intake is uncertain or poor:

• Safer approach: Administer prandial insulin immediately after the patient eats, with dose adjusted for the amount actually ingested 1

Critical Pitfalls to Avoid

Do NOT Use These Regimens

Sliding scale insulin alone as the sole treatment is strongly discouraged for prolonged use in hospitalized patients 1. While it has lower hypoglycemia risk, it provides inadequate glycemic control 1.

Premixed insulin (70/30 NPH/regular) is not recommended in the hospital setting due to unacceptably high rates of iatrogenic hypoglycemia 1.

Hypoglycemia Risk Management

The basal-bolus approach carries a 4-6 times higher risk of hypoglycemia compared to sliding scale insulin alone 1:

• Risk ratio 5.75 (95% CI 2.79-11.83) for blood glucose ≤3.9 mmol/L (70 mg/dL) 1
• Risk ratio 4.21 (95% CI 1.61-11.02) for blood glucose ≤3.3 mmol/L (60 mg/dL) 1

In controlled settings, mild hypoglycemia occurs in 12-30% of patients on basal-bolus regimens 1. However, this must be balanced against the improved glycemic control and reduced complications 1.

Insulin Selection

Preferred basal insulins: 2

• Insulin glargine (100 U/mL)
• Insulin detemir
• Insulin degludec

Preferred rapid-acting insulins: 1

• Insulin lispro
• Insulin aspart
• Insulin glulisine

Both glargine and detemir provide equivalent glycemic control in hospitalized patients, though detemir may require higher total daily doses (0.27 vs 0.22 U/kg/day) 3.

Monitoring and Adjustment

Increase frequency of blood glucose monitoring during insulin regimen changes 2. Target glucose ranges in the hospital are typically 7.8-10.0 mmol/L (140-180 mg/dL) for most non-critically ill patients 1.

Implement a hypoglycemia prevention and management protocol as many episodes are preventable 1.