Target Blood Glucose to Maintain
For most hospitalized patients, insulin therapy should be initiated when blood glucose persistently exceeds 180 mg/dL, with a target range of 140-180 mg/dL for both critically ill and non-critically ill patients. 1
Hospitalized Patients
Critically Ill (ICU) Patients
- Start insulin therapy when blood glucose is ≥180 mg/dL on two separate occasions 1
- Target range: 140-180 mg/dL (7.8-10.0 mmol/L) for the majority of critically ill patients 1
- More stringent targets of 110-140 mg/dL may be considered for select patients (e.g., post-cardiac surgery) only if achievable without significant hypoglycemia 1
- Avoid targets <110 mg/dL - the NICE-SUGAR trial demonstrated that intensive glucose control targeting 81-108 mg/dL increased mortality by 2% compared to targets of 140-180 mg/dL 1, 2
Non-Critically Ill Hospitalized Patients
- Target range: 100-180 mg/dL (5.6-10.0 mmol/L) for patients with new hyperglycemia or known diabetes 1
- Premeal glucose targets: <140 mg/dL (7.8 mmol/L) 1
- Random blood glucose: <180 mg/dL (10.0 mmol/L) 1
- Reassess insulin regimen if blood glucose falls below 100 mg/dL to prevent hypoglycemia 1, 3
- Fasting glucose <100 mg/dL predicts hypoglycemia within the next 24 hours 1, 3
Special Hospital Populations
- Terminally ill patients: Glucose levels up to 250 mg/dL (13.9 mmol/L) may be acceptable to minimize treatment burden 1
- Older/high-risk patients: Target range of 70-180 mg/dL with >50% time in range, accepting <10% of readings >250 mg/dL 1
Outpatient/Ambulatory Patients (Non-Pregnant Adults)
Standard Targets
- Preprandial (fasting) glucose: 80-130 mg/dL for most non-pregnant adults with diabetes 3
- Postprandial glucose (1-2 hours after meals): <180 mg/dL 3
- These targets correlate with achieving an A1C <7% 3
Individualized Targets Based on Patient Factors
More Stringent Goals (70-120 mg/dL fasting) may be appropriate for: 3
- Newly diagnosed diabetes with short disease duration
- Long life expectancy
- Absent or minimal comorbidities
- No history of severe hypoglycemia
Less Stringent Goals (>130 mg/dL fasting acceptable) may be appropriate for: 3
- Long-standing diabetes with established complications
- Limited life expectancy
- Severe comorbidities
- History of hypoglycemia unawareness
Continuous Glucose Monitoring Targets
- Time in range (70-180 mg/dL): >70% of readings (>16 hours, 48 minutes per day) for type 1 and type 2 diabetes 1
- Time below range (<70 mg/dL): <4% of readings (<1 hour per day) 1
- Time above range (>180 mg/dL): <25% of readings (<6 hours per day) 1
Critical Pitfalls to Avoid
- Never target glucose <110 mg/dL in critically ill patients - this increases mortality risk by 10-15 fold rates of hypoglycemia 1
- Do not administer insulin when blood glucose is <70 mg/dL - treat hypoglycemia first 4, 5
- Avoid relying solely on fasting glucose - check postprandial values to identify excessive excursions 3
- Do not ignore hypoglycemia risk factors: renal impairment, liver disease, elderly patients, and discontinuous nutritional intake increase risk 4, 5
- Avoid point-of-care capillary glucose testing in critically ill patients on vasopressors - arterial blood gas measurements are more accurate 1
- Minimize glycemic variability - wide glucose swings are associated with higher mortality independent of mean glucose levels 1, 6
Practical Implementation Algorithm
Step 1: Determine patient category
- Critically ill ICU patient → Target 140-180 mg/dL 1
- Non-critically ill hospitalized → Target 100-180 mg/dL (premeal <140 mg/dL) 1
- Outpatient with diabetes → Target fasting 80-130 mg/dL, postprandial <180 mg/dL 3
Step 2: Initiate insulin therapy
- Start when glucose ≥180 mg/dL on two occasions (hospitalized patients) 1
- Use intravenous insulin for critically ill patients 1
- Use subcutaneous basal-bolus regimens for non-critically ill 1
Step 3: Monitor for hypoglycemia