Diabetes Mellitus in Hospitalized Patients

Diabetes Mellitus in Hospitalized Patients is a topic covered in the Washington Manual of Medical Therapeutics.

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General Principles

Diabetes-specific indications for hospitalization

  • Diabetic ketoacidosis (DKA) is characterized by a plasma glucose level of >250 mg/dL (13.9 mmol/L) in association with an arterial pH <7.30 or serum bicarbonate level of <15 mEq/L and moderate ketonemia or ketonuria; however, patients may present with ketoacidosis and lower glucose levels.1,2
  • Hyperosmolar hyperglycemic state (HHS) includes marked hyperglycemia (≥600 mg/dL [33.3 mmol/L]) and elevated serum osmolality (>320 mOsm/kg), often accompanied by impaired mental status.3
  • Hypoglycemia is an indication for hospitalization if it is induced by a sulfonylurea (SFU) medication, is due to a deliberate drug overdose, or results in coma, seizure, injury, or persistent neurologic change.
  • Newly diagnosed T1DM or newly recognized GDM can be indications for hospitalization, even in the absence of ketoacidosis.
  • Patients with T2DM are rarely admitted to the hospital for initiation or change in insulin therapy unless hyperglycemia is severe and associated with mental status change or other organ dysfunction.

Management of diabetes in hospitalized patients

Hyperglycemia (BG ≥140 mg/dL [7.8 mmol/L]) is a common finding in hospitalized patients and may be due to previously diagnosed diabetes, undiagnosed diabetes, medications, or stress-induced hyperglycemia. Up to 40% of general medical and surgical patients exhibit hyperglycemia, and approximately 80% of intensive care unit (ICU) patients will demonstrate transient or persistent hyperglycemia.1

  • Patients with T1DM should be clearly identified as such at the time of admission.
  • A1C can help identify previously undiagnosed diabetes in hospitalized patients and may assist with the evaluation of prior glucose control. A1C is not accurate in patients who are severely anemic, bleeding, or hemolyzing or who have been transfused.1
  • Data regarding use of noninsulin therapies in inpatients are increasing. Dipeptidyl peptidase 4 inhibitor use alone or with basal insulin may provide adequate glucose control with less hypoglycemia than basal-bolus insulin regimens.1
  • Medication reconciliation on admission should include a careful assessment of home diabetes medications, level of glucose control, kidney function, expected diagnostic studies and treatments, and the possible need for insulin treatment.
  • Patients who are required to fast for diagnostic testing or treatments should have all noninsulin therapies stopped.
  • Patients hospitalized for reasons other than diabetes and who are eating normally may continue or restart outpatient diabetes treatments, unless specifically contraindicated.
  • Use of noninsulin therapies may be appropriate in psychiatric units, rehabilitation settings, or stable patients preparing for discharge.
  • Glucose targets for inpatients aim to reduce morbidity and mortality, while minimizing hypoglycemia.
    • In critical care settings, the glucose target is 140–180 mg/dL (7.8–10.0 mmol/L) with frequent monitoring recommended to avoid hypoglycemia.1
    • In noncritical care settings, the glucose target is <140 mg/dL (7.8 mmol/L) fasting and premeal and <180 mg/dL (10.0 mmol/L) postmeal or on a random glucose check with reassessment of the insulin regimen if glucose falls below 100 mg/dL (5.6 mmol/L).1,2,4

Management of hyperglycemia in critical care settings

  • Variable IV insulin infusion is recommended for critical illness, emergency surgery, or major surgery. Numerous algorithms have been published that direct insulin dose adjustments based on capillary BG values performed hourly at the bedside.
  • An IV infusion of a dextrose-containing solution or other caloric source should be provided to prevent hypoglycemia and ketosis. For fluid-restricted patients, 10% dextrose in water (D10W) can be infused at a rate of 10–25 mL/h to provide a steady, consistent source of calories.
  • An intermediate- or long-acting insulin should be given 2 hours prior to insulin infusion discontinuation.

Management of hyperglycemia in non–critical care hospital settings

  • BG should be checked on admission in all patients and monitored four times per day in hyperglycemic patients, especially in patients treated with insulin.
  • Scheduled insulin with basal, nutritional, and correction components provides superior glycemic control compared with correction or “sliding scale” insulin alone.1,2,4
  • For patients who are naïve to insulin, the starting dose of basal insulin should equal 0.1–0.2 units/kg. Scheduled premeal insulin should be 0.1–0.2 units/kg divided by three meals.

    Example: Your patient weighs 80 kg. The starting insulin dose should be 8–16 units of long-acting insulin plus 3–5 units of rapid-acting insulin before each meal. A correction dose of 1–2 units per 50 mg/dL (2.8 mmol/L) of BG, beginning at 140 mg/dL(7.8 mmol/L), can be added to the premeal doses.

  • Patients with T1DM should continue their home insulin doses and may continue the use of an insulin pump if there is a hospital policy in place to do so. Insulin doses in patients with T2DM should be reduced by 20%–40% on admission. If their home insulin dose is excessive compared with a weight-based dose of 0.4–0.5 units/kg or distribution between basal and premeal insulin is uneven, further reductions and adjustments may be necessary.
  • Meal-time insulin doses should be given shortly before or immediately after meals, and the correction factor or sliding scale dose should be added to the premeal dose.
  • The glucose threshold for sliding scale (corrective) insulin should be higher at bedtime, or corrective insulin should not be given at bedtime. Adjustments in the next-day basal or premeal insulin doses are indicated if correction doses of insulin are frequently required or if clinical status or medications change.
  • Extreme hyperglycemia (≥300 mg/dL [16.7 mmol/L]) on one or more consecutive tests should prompt testing for ketoacidosis with electrolytes and ketone measurements.
  • Hypoglycemia should be treated promptly with oral or IV glucose, and the capillary BG should be repeated every 10 minutes until >100 mg/dL (5.5 mmol/L) and stable. Reevaluation of scheduled doses and assessment of risk factors for hypoglycemia (declining renal function, hepatic impairment, poor intake) should be undertaken for any BG <70 mg/dL (3.9 mmol/L).1
  • Enteral nutrition: Intermittent tube feeds should be matched by either short-acting (human regular) insulin or intermediate-acting (human NPH [neutral protamine Hagedorn]) insulin. Patients with baseline hyperglycemia may need a basal insulin dose in addition to the doses given to cover tube feeds. For example, nighttime enteral feeding lasting 6–8 hours should be managed with NPH, with or without a basal insulin dose. NPH can be given three to four times daily for continuous tube feeds, allowing a change in insulin dose if the feeding is interrupted.1,2,4
  • Total parenteral nutrition (TPN): Patients supported with TPN are likely to develop hyperglycemia, and some require large amounts of insulin. See Chapter 2, Nutrition Support, for insulin management of patients on TPN.

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General Principles

Diabetes-specific indications for hospitalization

  • Diabetic ketoacidosis (DKA) is characterized by a plasma glucose level of >250 mg/dL (13.9 mmol/L) in association with an arterial pH <7.30 or serum bicarbonate level of <15 mEq/L and moderate ketonemia or ketonuria; however, patients may present with ketoacidosis and lower glucose levels.1,2
  • Hyperosmolar hyperglycemic state (HHS) includes marked hyperglycemia (≥600 mg/dL [33.3 mmol/L]) and elevated serum osmolality (>320 mOsm/kg), often accompanied by impaired mental status.3
  • Hypoglycemia is an indication for hospitalization if it is induced by a sulfonylurea (SFU) medication, is due to a deliberate drug overdose, or results in coma, seizure, injury, or persistent neurologic change.
  • Newly diagnosed T1DM or newly recognized GDM can be indications for hospitalization, even in the absence of ketoacidosis.
  • Patients with T2DM are rarely admitted to the hospital for initiation or change in insulin therapy unless hyperglycemia is severe and associated with mental status change or other organ dysfunction.

Management of diabetes in hospitalized patients

Hyperglycemia (BG ≥140 mg/dL [7.8 mmol/L]) is a common finding in hospitalized patients and may be due to previously diagnosed diabetes, undiagnosed diabetes, medications, or stress-induced hyperglycemia. Up to 40% of general medical and surgical patients exhibit hyperglycemia, and approximately 80% of intensive care unit (ICU) patients will demonstrate transient or persistent hyperglycemia.1

  • Patients with T1DM should be clearly identified as such at the time of admission.
  • A1C can help identify previously undiagnosed diabetes in hospitalized patients and may assist with the evaluation of prior glucose control. A1C is not accurate in patients who are severely anemic, bleeding, or hemolyzing or who have been transfused.1
  • Data regarding use of noninsulin therapies in inpatients are increasing. Dipeptidyl peptidase 4 inhibitor use alone or with basal insulin may provide adequate glucose control with less hypoglycemia than basal-bolus insulin regimens.1
  • Medication reconciliation on admission should include a careful assessment of home diabetes medications, level of glucose control, kidney function, expected diagnostic studies and treatments, and the possible need for insulin treatment.
  • Patients who are required to fast for diagnostic testing or treatments should have all noninsulin therapies stopped.
  • Patients hospitalized for reasons other than diabetes and who are eating normally may continue or restart outpatient diabetes treatments, unless specifically contraindicated.
  • Use of noninsulin therapies may be appropriate in psychiatric units, rehabilitation settings, or stable patients preparing for discharge.
  • Glucose targets for inpatients aim to reduce morbidity and mortality, while minimizing hypoglycemia.
    • In critical care settings, the glucose target is 140–180 mg/dL (7.8–10.0 mmol/L) with frequent monitoring recommended to avoid hypoglycemia.1
    • In noncritical care settings, the glucose target is <140 mg/dL (7.8 mmol/L) fasting and premeal and <180 mg/dL (10.0 mmol/L) postmeal or on a random glucose check with reassessment of the insulin regimen if glucose falls below 100 mg/dL (5.6 mmol/L).1,2,4

Management of hyperglycemia in critical care settings

  • Variable IV insulin infusion is recommended for critical illness, emergency surgery, or major surgery. Numerous algorithms have been published that direct insulin dose adjustments based on capillary BG values performed hourly at the bedside.
  • An IV infusion of a dextrose-containing solution or other caloric source should be provided to prevent hypoglycemia and ketosis. For fluid-restricted patients, 10% dextrose in water (D10W) can be infused at a rate of 10–25 mL/h to provide a steady, consistent source of calories.
  • An intermediate- or long-acting insulin should be given 2 hours prior to insulin infusion discontinuation.

Management of hyperglycemia in non–critical care hospital settings

  • BG should be checked on admission in all patients and monitored four times per day in hyperglycemic patients, especially in patients treated with insulin.
  • Scheduled insulin with basal, nutritional, and correction components provides superior glycemic control compared with correction or “sliding scale” insulin alone.1,2,4
  • For patients who are naïve to insulin, the starting dose of basal insulin should equal 0.1–0.2 units/kg. Scheduled premeal insulin should be 0.1–0.2 units/kg divided by three meals.

    Example: Your patient weighs 80 kg. The starting insulin dose should be 8–16 units of long-acting insulin plus 3–5 units of rapid-acting insulin before each meal. A correction dose of 1–2 units per 50 mg/dL (2.8 mmol/L) of BG, beginning at 140 mg/dL(7.8 mmol/L), can be added to the premeal doses.

  • Patients with T1DM should continue their home insulin doses and may continue the use of an insulin pump if there is a hospital policy in place to do so. Insulin doses in patients with T2DM should be reduced by 20%–40% on admission. If their home insulin dose is excessive compared with a weight-based dose of 0.4–0.5 units/kg or distribution between basal and premeal insulin is uneven, further reductions and adjustments may be necessary.
  • Meal-time insulin doses should be given shortly before or immediately after meals, and the correction factor or sliding scale dose should be added to the premeal dose.
  • The glucose threshold for sliding scale (corrective) insulin should be higher at bedtime, or corrective insulin should not be given at bedtime. Adjustments in the next-day basal or premeal insulin doses are indicated if correction doses of insulin are frequently required or if clinical status or medications change.
  • Extreme hyperglycemia (≥300 mg/dL [16.7 mmol/L]) on one or more consecutive tests should prompt testing for ketoacidosis with electrolytes and ketone measurements.
  • Hypoglycemia should be treated promptly with oral or IV glucose, and the capillary BG should be repeated every 10 minutes until >100 mg/dL (5.5 mmol/L) and stable. Reevaluation of scheduled doses and assessment of risk factors for hypoglycemia (declining renal function, hepatic impairment, poor intake) should be undertaken for any BG <70 mg/dL (3.9 mmol/L).1
  • Enteral nutrition: Intermittent tube feeds should be matched by either short-acting (human regular) insulin or intermediate-acting (human NPH [neutral protamine Hagedorn]) insulin. Patients with baseline hyperglycemia may need a basal insulin dose in addition to the doses given to cover tube feeds. For example, nighttime enteral feeding lasting 6–8 hours should be managed with NPH, with or without a basal insulin dose. NPH can be given three to four times daily for continuous tube feeds, allowing a change in insulin dose if the feeding is interrupted.1,2,4
  • Total parenteral nutrition (TPN): Patients supported with TPN are likely to develop hyperglycemia, and some require large amounts of insulin. See Chapter 2, Nutrition Support, for insulin management of patients on TPN.

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