Inpatient management of hyperglycemia

Hyperglycemia is a common occurrence in hospitalized patients and for inpatients is defined as a blood glucose (BG) level > 140 mg/dL. Common causes of hyperglycemia in hospitalized patients include underlying diabetes mellitus, medications (e.g., corticosteroids, thiazide diuretics), parenteral nutrition, and stress (e.g., due to surgery, trauma, or sepsis). Regardless of the cause, hyperglycemia is associated with longer hospital stays and worse outcomes. A structured, methodical approach to hyperglycemia is key to good glycemic control in hospitalized patients. When managing blood sugar levels, special care should be taken to avoid potentially life-threatening hypoglycemia, which can occur as a complication of insulin therapy. For more information, see diabetes mellitus and insulin.

1. Rule out hyperglycemic crises.
2. Identify (and treat) the underlying cause.
   • Underlying diabetes or glucose intolerance
     • Patient history
       • T1DM or T2DM or prior episodes of hyperglycemia
       • On insulin or oral antidiabetic medications
     • Check HbA1c (if not done in the past 3 months). ^[1]
     • See also screening for diabetes mellitus.
   • Medication-induced (see “Differential diagnoses” below)
   • Enteral or parenteral nutrition
   • Stress-induced (e.g., sepsis, recent surgery, trauma)
3. Determine whether to initiate insulin therapy.
   • Insulin therapy is generally recommended for persistently elevated glucose ≥ 180 mg/dL. ^[1]
   • The goal is moderate glycemic control (glucose range: 140–180 mg/dL). ^[1][2]
4. Start an appropriate insulin regimen, if indicated (see insulin regimens).
5. Monitor and adjust therapy as needed:
   • NPO or continuous enteral feeding: Check POC glucose every 4–6 hours.
   • Patient is eating: Check POC glucose before every meal and at bedtime.
   • Patients receiving intravenous insulin: Check POC glucose every 30–120 minutes.
   • BMP every 1–2 days to monitor creatinine and serum glucose.
6. Avoid (and treat) hypoglycemia (generally defined as ≤ 70 mg/dL, see hypoglycemia). ^[1]
7. Consider endocrine consult or hyperglycemia team consult if glucose is difficult to control.

Hyperglycemic crisis (DKA and HHS) must be ruled out in all hyperglycemic patients.

Target glucose may vary depending on individual patient factors (e.g., more liberal goals for terminally ill patients may be acceptable).

• Indications for insulin therapy
  • T1DM: should always be continued on insulin therapy
  • T2DM: repeated elevated random or premeal blood glucose ≥ 180 mg/dL ^[1]
• Recommended insulin regimen
  • A basal-bolus insulin regimen is preferable. ^[3][4]
  • Prolonged use of a sliding scale insulin regimen is discouraged. ^[5][6]
• Monitoring
  • Patient is NPO or on continuous enteral feeding: Check POC glucose every 4–6 hours.
  • Patient is eating: Check POC glucose before every meal and at bedtime.
  • BMP every 1–2 days to monitor creatinine and serum glucose
• Other considerations
  • Ensure the patient is on a consistent carbohydrate diet.
  • Hold oral antidiabetic drugs (e.g., metformin).
  • Check serum HbA1c for baseline (if no recent values available).

• Indication for insulin therapy: blood glucose > 180 mg/dL ^[1]
• Recommended insulin regimen
  • Continuous intravenous insulin infusion (IIP) is preferable. ^[1][7]
  • Avoid IIP in the following situations:
    • Rapid normalization of glucose expected
    • Patients close to transfer to a general ward
    • Terminally-ill patients
    • Patients who are eating
  • For patients not on IIP, a basal-bolus insulin regimen is usually appropriate
• Monitoring: POC glucose hourly, if on a continuous insulin infusion
• Other considerations: Ideal glucose targets for critically ill patients are still under discussion.

• Screening for hyperglycemia ^[8][9]
  • POC glucose every 6 hours for 24–48 hours
  • Discontinue screening if glucose levels are < 140 mg/dL for 48 hours in nondiabetic patients.
• Indications for insulin therapy: Consider insulin therapy if blood glucose ≥ 140 mg/dL.
• Recommended insulin regimen (see “Insulin regimens for glucocorticoid-induced hyperglycemia” for details)
  • Different approaches
    • A basal-bolus regimen is preferable (especially for patients receiving dexamethasone).
    • Weight-based NPH insulin regimen for glucocorticoid-induced hyperglycemia (especially for patients receiving prednisone or prednisolone)
    • Correction only using a sliding-scale insulin regimen may be adequate for the short-term.
  • Monitoring
    • Patient is NPO or on continuous enteral feeding: Check POC glucose every 4–6 hours.
    • Patient is eating: Check POC glucose before every meal and at bedtime.
    • BMP every 1–2 days to monitor creatinine and serum glucose
  • Other considerations: Adjust the insulin regimen when changing the glucocorticoid dose.

An individual approach is necessary. For example, a patient with mild hyperglycemia who is on a low dose of glucocorticoids that is being tapered will require a different approach than a patient with glucose levels > 300 mg/dL on chronic high-dose glucocorticoids.

• Screening for hyperglycemia ^[6]
  • POC glucose every 4–6 hours for 24–48 hours
  • Discontinue screening if glucose levels are < 140 mg/dL for 48 hours in nondiabetic patients.
• Indications for insulin therapy ^[10]
  • Blood glucose > 180 mg/dL once
  • Blood glucose 140–180 mg/dL two times
• Recommended insulin regimen ^[1][6][10]
  • An adapted basal-bolus insulin regimen is preferable in patients receiving enteral nutrition.
  • Regular insulin can be added to parenteral nutrition solutions.
  • See insulin regimens for enteral and parenteral nutrition
• Monitoring: POC glucose every 4–6 hours
• Other considerations
  • Diabetes-specific formulas of enteral/parenteral nutrition should be given to help manage blood glucose levels.
  • Patients receiving enteral/parenteral nutrition are at high risk of hypoglycemia.

Patients with type 1 diabetes mellitus require basal insulin even if (enteral) feeding is discontinued.

Stress-induced hyperglycemia

• Many stressors can cause hyperglycemia (e.g., ACS, trauma, surgery). ^[11]
• Attempts should be made to identify and treat the underlying stressor.
• Glycemic management is otherwise similar to standard diabetes care (see “Patients with underlying diabetes mellitus” above).

Drug-induced hyperglycemia ^[8][9][12]

• Many drugs are associated with hyperglycemia (see Differential diagnoses of hyperglycemia).
• The decision to reduce or discontinue a drug should be made on an individual basis.
• Glycemic management is otherwise similar to standard diabetes care (see “Patients with underlying diabetes mellitus” above).

Patients on continuous subcutaneous insulin infusion (CSII) ^[13]

• CSII (i.e., insulin pump) is usually discontinued when patients are admitted to the hospital.
• Continuation of CSII may be considered in select patients if:
  • The patient demonstrates the capacity to use the pump correctly.
  • No contraindications for CSII are present, e.g.:
    • Patient unable to participate actively in blood sugar management
    • An altered state of consciousness
    • DKA
    • Severe illness (e.g., sepsis)
    • Need for MRI
    • Suicidal ideation
• If CSII is discontinued, a basal-bolus insulin regimen is recommended.

Every patient switched from continuous subcutaneous insulin infusion to another insulin regimen should receive basal insulin.

• Medications ^[12]
  • Fluoroquinolones
  • Beta blockers
  • Thiazide diuretics and loop diuretics
  • Heparin
  • Glucocorticoids
  • Calcineurin inhibitors
  • Tricyclic antidepressants
  • Antipsychotic drugs
  • Lithium
  • HIV-protease inhibitors
  • Thyroid hormones (e.g., levothyroxine)
  • Estrogen (contraceptives)
  • Sympathomimetic drugs that interact with the beta-1 adrenergic receptor (e.g., dobutamine)
  • Derivatives of nicotinic acid
• Pancreatic disorders
  • Acute and chronic pancreatitis
  • Hemochromatosis
  • Cystic fibrosis
  • Pancreatic cancer
  • Glucagonoma
• Endocrine
  • T1DM
  • T2DM
  • Gestational diabetes
  • Hyperthyroidism
  • Primary hypercortisolism
    • Adrenal adenoma
    • Adrenal carcinoma
    • Macronodular adrenal hyperplasia
  • Secondary hypercortisolism
    • Pituitary adenoma
    • Small cell lung cancer
    • Renal cell carcinoma
  • Growth hormone-secreting pituitary adenoma (acromegaly)
  • Pheochromocytoma
• Stress
  • Sepsis
  • Trauma
  • Recent surgery
• Polycystic ovary syndrome (PCOS) ^[14]

The differential diagnoses listed here are not exhaustive.

• Rule out hyperglycemic crisis.
• Rule out sepsis, other reversible causes of hyperglycemia.
• Check HbA1c.
• Hold any medications that may be contributing.
• Ensure patient is on the correct diet (e.g., consistent carbohydrate).
• Start insulin therapy if indicated (see insulin regimens).
• Order monitoring parameters.
• Order hypoglycemia treatment protocol.
• Consider endocrine consult or hyperglycemia team consult if glucose is difficult to control despite appropriate insulin regimen.