Should infection-induced hyperglycemia be treated in patients with or without a history of diabetes?

Should You Treat Infection-Induced Hyperglycemia?

Yes, infection-induced hyperglycemia should be treated in both diabetic and non-diabetic patients, as hyperglycemia during infection is associated with increased mortality, infection complications, and impaired immune function, regardless of diabetes history. 1, 2, 3

Treatment Thresholds and Targets

For Critically Ill Patients

• Initiate insulin therapy when blood glucose exceeds 180 mg/dL (10 mmol/L), with a target range of 140-180 mg/dL for most critically ill patients. 1
• More stringent targets of 110-140 mg/dL may be appropriate for selected stable patients, provided this can be achieved without significant hypoglycemia risk. 1
• Use intravenous insulin protocols that have demonstrated safety and efficacy in achieving target ranges. 1

For Non-Critically Ill Hospitalized Patients

• Target premeal glucose <140 mg/dL with random glucose <180 mg/dL in patients receiving insulin therapy. 1
• The American Diabetes Association recommends starting glucose monitoring with orders for correction insulin immediately for any patient with infection-related hyperglycemia, even without known diabetes. 2
• For blood glucose >250 mg/dL with infection, insulin therapy should be strongly considered. 3

Why Treatment Is Critical

Immune System Impairment

• Hyperglycemia significantly impairs host defenses by decreasing polymorphonuclear leukocyte mobilization, chemotaxis, and phagocytic activity. 4, 5
• High glucose concentrations activate protein kinase C, which inhibits neutrophil migration, phagocytosis, superoxide production, and microbial killing. 5
• Hyperglycemia decreases the formation of neutrophil extracellular traps and can induce Toll-like receptor expression while inhibiting neutrophil function. 5

Clinical Outcomes

• Infection is more likely to necessitate hospitalization in patients with diabetes or hyperglycemia compared to those without. 1
• Hyperglycemia increases mortality rate, risk of postoperative nosocomial infection, need for ICU admission, length of hospital stay, and hospital charges. 6
• Intensive insulin therapy to maintain tight glucose control decreases morbidity and mortality in critically ill patients, with the principal benefit being a decrease in infection-related complications and mortality. 4

Insulin Regimen Selection

For Patients with Good Oral Intake

• Use a basal-bolus insulin regimen (basal, nutritional, and correction components) rather than sliding scale insulin alone, which is ineffective. 1, 3
• Calculate total daily insulin dose at 0.5-0.8 units/kg/day based on patient weight. 3
• Divide total daily dose into 50% basal insulin and 50% prandial insulin. 3

For Patients with Poor Oral Intake or NPO Status

• A basal plus correction insulin regimen is preferred for patients with poor oral intake or taking nothing by mouth. 1

For Glucocorticoid-Induced Hyperglycemia

• NPH insulin is the standard approach for once- or twice-daily short-acting glucocorticoids, administered concomitantly with the steroid dose because its peak action at 4-6 hours aligns with the steroid's peak hyperglycemic effect. 2

Monitoring Requirements

• Monitor blood glucose every 4-6 hours during acute illness in hospitalized patients. 3
• For critically ill patients, more frequent monitoring (every 2-4 hours) may be necessary while on insulin infusion protocols. 2
• Adjust insulin doses daily based on glucose monitoring results. 3

Metabolic Stabilization During Infection

Attending to the general metabolic state is essential and may involve restoration of fluid and electrolyte balances, correction of hyperglycemia, hyperosmolality, acidosis, and azotemia. 1

• The improvement of glycemic control may aid in both eradicating the infection and healing the wound. 1
• As the infection improves, hyperglycemia may become easier to control. 1
• The stress of illness frequently aggravates glycemic control and necessitates more frequent monitoring of blood glucose and urine or blood ketones. 1

Critical Pitfalls to Avoid

• Do not use sliding-scale insulin as monotherapy, as this approach is ineffective and may lead to wide glucose fluctuations. 3
• Avoid oral hypoglycemic agents during acute illness, especially if the patient has impaired oral intake. 3
• Never discontinue insulin completely in patients with type 1 diabetes, even when infection resolves. 3
• Avoid targeting overly strict glycemic control (<140 mg/dL) during acute illness, as this increases hypoglycemia risk. 3

Discharge Planning and Follow-Up

• Obtain an A1C in patients with hyperglycemia admitted to the hospital if results from the previous 3 months are not available. 1
• Patients with hyperglycemia who do not have a prior diagnosis of diabetes should have appropriate follow-up testing and care documented at discharge. 1, 2
• Provide diabetes self-management education focusing on medication adherence, glucose monitoring, and sick-day management. 3
• Once acute infection is controlled and the patient is eating regularly, consider transitioning to oral agents if appropriate. 3