diabetes blue book

Hyperglycemia inpatient

Any acute illness results in a state of stress with release of hormones (e.g. glucocorticoids) and cytokines, which in turn cause insulin resistance. This increased insulin resistance will exacerbate any underlying defect in carbohydrate metabolism leading to either overt diabetes mellitus or so called “stress hyperglycemia.” Patients admitted with known diabetes have a 3-fold increase in mortality and those admitted with “new-onset” hyperglycemia have an 18 fold increase in mortality.

Many patients with diabetes may be very well controlled as outpatients with one or more oral antidiabetes drugs (OADs) such as metformin, glyburide and sitagliptin. However, these medications require adequate levels of endogenous insulin to be effective. In the setting of acute illness and insulin resistance, it is common for the fasting blood glucose (BG) to exceed 200 mg/dl. When this happens, the patient’s endogenous insulin release is suppressed (so called glucose toxicity) and the BG can potentially exceed 400 mg /dl. BGs of over 500 mg/dl imply either absolute insulin deficiency in type 1 diabetes, or the presence of acute or chronic renal insufficiency or pre-renal azotemia in patients with type 2 diabetes. Pre-renal azotemia is common in the setting of dehydration caused by a hyperglycemic-induced osmotic diuresis. For this reason, all patients with diabetes (regardless of type) as well as those with stress hyperglycemia are best treated with both insulin therapy and appropriate intravenous fluids to control hyperglycemia during hospitalization.

Target Glucose

The optimal target range for plasma glucose in hospitalized non-pregnant adult patients is currently being debated. The current recommendations by the American Association of Clinical Endocrinologists and the American Diabetes Association for 2009 are shown in the table below.

Table 1: Recommended glycemic targets – hospitalized patients with diabetes

The American Diabetes Association recommends insulin therapy as the preferred method of glycemic control in the hospital setting in the majority of clinical situations. Physiological insulin replacement therapy will provide the best control and the greatest flexibility during hospitalization.

IV insulin is preferred for the management of hyperglycemia in critical care illness, hyperglycemic emergencies, and selected clinical situations when BG is otherwise difficult to control. Subcutaneous (subQ) basal-bolus regimens are generally recommended for most hospitalized patients. Patients given subQ insulin usually require all three insulin components: 1) basal, 2) nutritional and 3) correctional.

Basics

When hyperglycemia (i.e., blood glucose greater than 180mg/dl) is documented and confirmed, initiation or adjustment of insulin therapy to achieve glycemic control is required.

Initial dosing of subQ insulin is based on type of diabetes, weight, and renal function. It is optimally given with one or more of three components:

Diet

Order Consistent Carbohydrate Diet (20-25 cal/kg body weight), unless patient is NPO or receiving non-oral nutrition; may be added as a modifier to other diets (cardiac, clear liquids, etc.) See Table 3 for detailed information.

3 AM FSBS

3am FSBS is needed to assess morning BG and overnight control with basal insulin

Insulin absorption

types

If BG are labile, look for mistiming issues with BG measurement, mealtimes, and insulin administration (e.g., BG checked shortly after a meal, nutritional insulin given when patient did not eat). If so, be conservative with dose changes and discuss mistiming issues with nursing staff.

Lantus/Humalog to Humulin 70/30
Add Lantus and meal time Humalog daily dose to get total daily dose
Give ⅔ of TDD as 70/30 in am 30 minutes before breakfast
Give ⅓ of TDD at 70/30, 30 minutes before last meal of day

Hold nutritional insulin (Humalog, Regular) IF AND ONLY IF patient is NPO or nutrition is interrupted, refused, or very limited. Unless specifically ordered, the current FSBS does not impact the order for nutritional insulin.

Acute and Chronic Kidney Disease

Hypoglycemia is the major concern for CKD patients who are treated with insulin or sulfonylureas. There are several reasons for this propensity to hypoglycemia. First, insulin is metabolized by the kidney. As kidney function is lost, insulin is not cleared normally and both endogenous and exogenous insulin circulate for a much longer period of time. For example, regular insulin may last 6-12 hours instead of typically 4-6 hours with normal renal function. Sulfonylureas are contraindicated in diabetic patients with CKD since they can cause severe hypoglycemia for several days.

Secondly, patients with CKD are prone to hypoglycemia because of the loss of substrate from renal gluconeogenesis. Normally the kidney converts alanine and other amino acids into glucose in the fasting state. With kidney failure this source of calories is lost. If the patient is also eating poorly from uremia or other conditions, their hepatic glycogen may be depleted. In this situation (poor nutrition) there will be limited substrate to mobilize and hypoglycemia from exogenous insulin can be severe and even life-threatening. Most hypoglycemic deaths are felt to be secondary to cardiac arrhythmias.

The dextrose concentration in the dialysis fluid may also affect blood glucose levels (typically increase after peritoneal dialysis and decrease after hemodialysis).

Exercise caution in interpreting hemoglobin A1c levels; they may be falsely low in the presence of hemodialysis, recent blood transfusions, or erythropoietin administration. Insulin dosing at admission

Insulin pharmacokinetics are greatly impacted by ESRD

Steroid-Induced Hyperglycemia

All inpatients receiving steroids should have point-of-care BG monitoring for the first 24-48 hours to determine if hyperglycemia is present.

When commonly used steroids (e.g., prednisone) are administered once daily in the morning, marked post-prandial hyperglycemia is often seen. When multiple daily doses are administered, or long acting steroids (especially dexamethasone) are used, hyperglycemia is noted throughout the day, including when fasting.

When persistent hyperglycemia (>180mg/dl x2) is documented, treatment is necessary and glycemic goals are the same as for patients with known diabetes. In patients with diabetes, insulin needs may significantly increase when they are receiving oral or intravenous corticosteroids.

Use of correctional insulin alone for patients with steroid-induced hyperglycemia is not recommended since it has been consistently shown to be inferior.

Basal-bolus subQ insulin regimens may be used to effectively control hyperglycemia. However, IV insulin infusions are indicated if BG is consistently >300mg/ml. Modified basal-bolus regimens which contain a lower proportion of basal insulin (30%), and a higher proportion of nutritional insulin (70%), in contrast to the typical 50/50 ratio, are recommended. Lower basal doses also reduce the risk of nighttime or fasting hypoglycemia during steroid tapers.

Proactive reductions during steroid tapers will prevent hypoglycemia. As a rule of thumb, 10-20% reductions in insulin doses may be required for each reduction in steroid dose.

Initial Subcutaneous Insulin Dosing Recommendations
For patients WITHOUT pre-existing diabetes
If BG 140-180 mg/dl, start correctional insulin 5 times daily
If BG >180mg/dl x 2 in 24 hours, begin scheduled insulin 0.4
units/kg/day. (Reduce if GFR <50 ml/min, age >70, BMI <19.)
Divide into 30% basal and 70% nutritional.

For patients WITH pre-existing diabetes
If well-controlled with non-insulin therapies, follow
recommendations for patients WITHOUT pre-existing diabetes
If on insulin or poorly controlled diabetes
T1DM with BMI <25, 0.4 units/kg/day
T1DM/T2DM with BMI 25-30, 0.5 units/kg/day
T2DM with BMI >30, 0.6 units/kg/day
Reduce above daily insulin dose by 10-20% in patients at
high risk for hypoglycemia
Divide daily dose: 30% basal, 70% nutritional

perioperative

Peri-Operative Patients
Day before procedure

TPN

Total Parenteral Nutrition (TPN): Use Subcutaneous Insulin Order Set
• Check FSBS every 6 hours.
• Order correctional regular insulin every 6 hours using weight-based
ISF and target 140mg/dl.
• Patients with pre-existing diabetes will need basal insulin.
• Nutritional insulin component may be added to TPN or given on a
scheduled basis as regular insulin every 6 hours; adjust as needed.
Nutritional insulin up to 60% of the total daily dose may be required.
• Note: In patients with End Stage Renal Disease, lispro (Humalog) is
preferred, and may be given every 6 hours.
• The sole use of long-acting insulin is discouraged. Sudden
discontinuation or interruption of feedings can translate into severe
hypoglycemia.
Enteral Nutrition: Use Subcutaneous Insulin Order Set
• Continuous Tube Feedings - Managed like TPN

Starting dose

Calculate Corrective (Supplemental) Insulin: a. Weight Based (Wake One order set is based on Type of DM and weight): 3400 ÷ weight (kg) = Insulin Sensitivity Factor (ISF) b. Based on TDD If Known: 1700 ÷ TDD = Insulin Sensitivity Factor (ISF)

For dosing based on TDD: each class of non-insulin anti-diabetic agent (e.g. sulfonylurea, metformin) as equivalent to 20-30 units of insulin. Proportional decreases in insulin equivalency when dosed less than maximally.

Transitioning from IV to Subcutaneous Insulin: Must give first subcutaneous basal insulin dose at least 2 hours before stopping IV insulin!

  1. Estimate hourly insulin rate in units per hour over past 4 hours.
  2. Multiply this rate by 24 hours to estimate total IV insulin need per 24 hours.
  3. Use 80% of this 24 hour total as initial Basal Insulin dose per 24 hours.
  4. If patient eating, add Prandial Insulin (eg. Lispro) starting at 0.1 unit/kg body weight SQ TID pc each meal. (Hold dose if unable to eat).
  5. Order corrective insulin based on weight or TDD
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