What is the recommended management of hyperglycemia in a patient with acute ischemic stroke and uncontrolled type 2 diabetes according to the American Heart Association (AHA) - American Stroke Association (ASA) guideline 2021?

Management of Hyperglycemia in Acute Ischemic Stroke with Uncontrolled Type 2 Diabetes

According to the 2018 AHA/ASA guidelines (the most recent comprehensive stroke guidelines), initiate insulin therapy when blood glucose persistently exceeds 180 mg/dL, targeting a range of 140-180 mg/dL, and closely monitor to prevent hypoglycemia. 1

Current AHA/ASA Guideline Recommendations (2018)

The 2018 guidelines provide a Class IIa recommendation (Level of Evidence C-LD) that it is reasonable to treat hyperglycemia to achieve blood glucose levels in a range of 140-180 mg/dL during the first 24 hours after acute ischemic stroke. 1 This represents the most current AHA/ASA position and supersedes earlier recommendations.

Key points from the 2018 guidelines:

• Persistent in-hospital hyperglycemia during the first 24 hours after stroke is associated with worse outcomes than normoglycemia 1
• Hypoglycemia (blood glucose <60 mg/dL) must be treated immediately with the goal to achieve normoglycemia (Class I recommendation) 1
• The target range of 140-180 mg/dL balances the risks of hyperglycemia against the dangers of hypoglycemia 1

Evolution from Earlier Guidelines

The 2013 AHA/ASA guidelines contained identical recommendations regarding the 140-180 mg/dL target range. 1 The 2007 guidelines suggested a more aggressive threshold, recommending treatment for blood glucose >140 mg/dL, but acknowledged the lack of definitive data. 1

The consensus has shifted toward:

• Higher treatment thresholds (180 mg/dL vs 140 mg/dL) 1, 2
• Moderate rather than tight glycemic control 2
• Greater emphasis on avoiding hypoglycemia 1, 2

Evidence Supporting the 140-180 mg/dL Target

The American Diabetes Association recommends maintaining blood glucose in a range of 140-180 mg/dL in all hospitalized patients with acute stroke, as aggressively lowering glucose levels does not improve outcomes and increases the risk of hypoglycemia. 2 This recommendation is supported by:

• The SHINE trial (2019), the largest randomized trial to date with 1,151 patients, which found that intensive glucose control (target 80-130 mg/dL) versus standard control (target 80-179 mg/dL) showed no difference in functional outcomes at 90 days but resulted in significantly more severe hypoglycemia (2.6% vs 0%) 3
• Meta-analyses showing increased rates of severe hypoglycemia and mortality in tightly controlled cohorts compared to moderate control 2
• The GIST-UK trial, which showed no clinical benefit from aggressive glucose lowering despite achieving lower glucose levels 2

Practical Implementation Algorithm

Step 1: Initiate insulin therapy when:

• Blood glucose persistently exceeds 180 mg/dL 1, 2
• For critically ill patients or those receiving thrombolytic therapy, consider intravenous insulin protocols 4

Step 2: Target range:

• Maintain blood glucose between 140-180 mg/dL 1, 2
• Monitor blood glucose every 1-2 hours initially during insulin infusion 5

Step 3: Insulin delivery method:

• Intravenous insulin is preferred for critically ill patients, those receiving thrombolytics, or those with extreme/persistent hyperglycemia for the first 24-48 hours 4
• Subcutaneous insulin protocols can safely maintain glucose levels in the target range for stable patients 2
• Transition to subcutaneous basal-bolus regimen after stabilization 4

Step 4: Hypoglycemia prevention:

• Treat any blood glucose <60 mg/dL immediately 1
• Avoid targeting normoglycemia or levels <140 mg/dL 2
• Monitor closely during nighttime hours when hypoglycemia is most common 6, 7

Critical Pitfalls to Avoid

Do not target normoglycemia or aggressive control (<140 mg/dL): The evidence clearly demonstrates this increases hypoglycemia risk without improving outcomes. 2, 3 Hypoglycemia can cause permanent brain damage and worsen ischemic injury. 2

Do not delay treatment of persistent hyperglycemia >180 mg/dL: Multiple observational studies show that persistent hyperglycemia during the first 24 hours is associated with infarct expansion, hemorrhagic transformation, and poor neurological outcomes. 1, 2

Do not rely on pre-meal capillary glucose testing alone: Continuous glucose monitoring studies reveal that conventional testing misses nocturnal and dawn hyperglycemic patterns that occur in 50% of acute stroke patients. 6, 7

Do not use sliding scale insulin alone: This reactive approach is strongly discouraged and ineffective for glycemic management in acute stroke. 4 Use scheduled basal-bolus regimens instead.

Special Considerations for Uncontrolled Type 2 Diabetes

For patients with pre-existing uncontrolled diabetes (as implied by your question), the acute stroke setting requires:

• More frequent glucose monitoring due to unpredictable stress-induced glucose fluctuations 4
• Continuation of metformin if the patient was previously taking it (unless contraindicated), as this reduces total insulin requirements 4
• Transition planning for long-term diabetes management after the acute phase, as the patient will need intensification of their outpatient regimen 4

The 2018 AHA/ASA guidelines represent the current standard of care, recommending a treatment threshold of 180 mg/dL with a target range of 140-180 mg/dL. 1 This approach is consistent with American Diabetes Association recommendations for critically ill patients and is supported by the most recent high-quality evidence showing that more aggressive control increases harm without improving outcomes. 2, 3