Glucose Management in the Hospital

By Bruce W. Bode, M.D., FACE

From ATLANTA Medicine, Vol. 85, No. 4

Elevated glucose in the hospital is very common, occurring in more than 38 percent of patients. The presence of hyperglycemia has been shown to increase morbidity and mortality as well as total cost of care^1,2.

Over one third of these patients have newly discovered hyperglycemia and are confirmed upon testing as having pre-exiting diabetes¹. Studies have shown that patients with unrecognized diabetes have three times greater mortality and morbidity than those with recognized diabetes¹. If diabetes is not addressed during the hospital stay, in addition to morbidity and mortality being increased, readmission rates are as high as 31 percent in this population³.

Studies to obtain near normalize glucose in the hospital environment have had mixed results, often due to unacceptable hypoglycemia (BG <40 mg/dL), which in itself increases mortality^4,5,6. When hypoglycemia is avoided, recent studies have shown very low rates in morbidity or mortality with a reduction in total cost of care when glucose is controlled in the 100 to 140 mg/dL range compared to 140 to 180 mg/dL range^7,8.

Based on the above facts, it is essential for all hospitals to have protocols to identify all patients with hyperglycemia, to treat patients safely to near normal glucose without hypoglycemia, and to discharge the patient with a case-specific plan to manage their glucose in a near normal range until seen by their primary care team.

There are steps a hospital or hospital system should do to minimize the impact of hyperglycemia in the hospital. The majority of these steps have been implemented at the Piedmont Hospital, Atlanta campus.

Identify Patients with Hyperglycemia

1. Screen all high-risk patients with a fingerstick point-of-care glucose (POC) measurement upon admission to the ICU or hospital floor. High risk is defined as patients prone to diabetes or hyperglycemia, which include all patients who are elderly, are obese, have an infection, have cardiovascular disease, are in the ICU, are on steroids or have a known family history of diabetes.

2. If glucose is above 140 mg/dL, begin fingerstick POC testing AC TID and HS. If glucose is less than 140 mg/dL upon repeat testing, one can stop testing. If glucose is greater than 140 mg/dL or in all patients with known diabetes, draw an A1C and implement correction dose insulin with rapid-acting insulin (lispro, aspart or glulisine) for any glucose above 140 mg/dL The formula we use is (BG-100)/correction factor equals units of rapid-acting insulin. The correction factor (CF) is often 40 to start but can be determined by two formulas: CF = 3000/weight in KG or CF = 1700/total daily dose of insulin.

Treatment of Hyperglycemia

1. If the patient’s pre-existing diabetes and glucose is controlled at home on basal bolus insulin, one can continue current insulin regimen and adjust accordingly to keep BG in a safe range (70 to 140 pre-meal and less than 180 post-meal). Always give the basal dose and correction dose but hold the meal dose if not eating. If patient is on pre-mixed insulin, it is best to transition them to basal bolus therapy listed below to avoid hypoglycemia.

2. If the patient is newly diagnosed with diabetes or pre-exiting diabetes with glucoses >180 mg/dl, one must start either SC or IV insulin therapy depending on whether the patient can eat or how high their glucose is.

3. If the patient is able to eat, not critically ill and glucose is less than 300 mg/dL, one can start weight-based insulin on the following formula: weight in KG times 0.5 (or times 0.3 in renal impaired or age >72 years old) equals the amount of total daily insulin (TDD). The basal dose (glargine or detemir) is 50 percent of the TDD given at bedtime. The meal dose (rapid-acting insulin) is 50 percent of the TDD divided by three given in proportion to the food (carbs) consumed at each meal.
   If half the meal is eaten, give one half the meal dose. A correction dose of rapid acting insulin is given for any BG > 140 mg/dL. The correction dose is BG-100/CF where CF is calculated by 1700/TDD. POC BG testing should be done AC TID, HS and 0300.
   As stated above, always give the basal dose and correction dose but hold the meal dose if not eating. One must adjust the individual basal and bolus doses to be in a safe and acceptable glucose range, ideally 70 to 140 mg/dL pre-meal, but higher targets may be acceptable (80 to 180 mg/dL). All oral agents should be stopped, especially sulfonylureas.

4. If the patient is critically ill, unable to eat or has a glucose >300 mg/dL, one should start IV insulin per hospital protocol. This is best done using a computerized system such as Glucommander^7,9 to avoid any hypoglycemia, obtain near normal glycemia in a reasonable time (<6 hours) as well as simplifying the workload on the nursing staff.
   The formula used in the Glucommander is (BG-60) x a multiplier equals units of IV regular insulin given every hour. The starting multiplier is 0.02 for all patients except in post-op CV patients we recommend a starting multiplier of 0.06⁸.
   POC glucose testing is done every hour till stable then every two hours. The computerized system adjusts the multiplier and tells the RN when to check the glucose and does all the calculations for the RN to get the glucose in a pre-specified glucose target range.
   At Piedmont, we use 100 to 140 mg/dL for all patients except CV surgery patients, for which we use 90 to 120 mg/dL. It is recommended to have dextrose containing IVFs; at Piedmont we use D10 at 50 ml/hr or D5 at 100 ml/hr. Potassium levels should monitored and adjusted at least daily and more often if out of range. Patients should not eat any calories while on IV insulin unless a meal dose is given to cover the carbs of that meal.

Once stable and able to eat, one should transition all known diabetes patients and any other patient with an A1C >6.5 percent to basal bolus therapy based on weight as listed above or using the current multiplier once at goal. The formula to calculate TDD based on the multiplier is 1,000 times the multiplier equals the TDD. The basal dose should be started at least four hours before stopping the IV insulin, and the bolus and correction dose should be given at meal times based on the above formulas.

If transitioning to enteral feedings, one should start basal insulin twice daily, given every 12 hours with correction dose insulin every four hours, and once stable, every six hours for any glucose >140 mg/dL. The total basal dose is 1,000 times the multiplier. The CF is 1700/TDD. The basal dose should be adjusted up and down by 20 percent to keep the glucose in an acceptable target range (80 to 160 mg/dL). If enteral feedings are temporarily stopped, one should start D10 at 50 ml/hr and hold the basal dose till enteral feedings are resumed.

If transitioning to TPN, one should add 80 percent of the TDD determined by the IV insulin requirement to the TPN and adjust daily to keep the glucose in acceptable range. If the patient has not been on IV insulin, one can add one unit of regular insulin for every 10 grams of dextrose in the TPN bag. Correction dose is given every four hours, and once stable every six hours for any BG >140 mg/dL.

Treatment of Hypoglycemia

1. All hospitals must have a hypoglycemia protocol. If glucose is <70 mg/dL and patient is conscious, one should treat with 15 grams of oral glucose and recheck in 15 minutes and retreat again as needed. If not able to swallow, give IV dextrose using the formula ml of D50 equals 100 minus the BG value or give ½ amp of D50 IV push.

2. Prevention of hypoglycemia is crucial by using the above formulas and adjusting insulin by 20 percent for any BG <80 mg/dL that was caused by that insulin. Also, giving insulin post meal in proportion to the food consumed also minimizes hypoglycemia. In addition, having a dedicated hyperglycemic team and using computerized IV and SC dosing system prevents most hypoglycemia. Raising glycemic targets higher (80 to 160 mg/dL or 100 to 160 mg/dL) in patients prone to hypoglycemia such as elderly or renal impaired is another option.

 Discharge Planning and Recommendations

1. Discharge planning is best started upon admission by screening and recognizing unrecognized diabetes and poorly controlled. If A1C is at goal upon admission without hypoglycemia, one can return to their prior pre-admission diabetes treatment. If A1C is not at goal, one must discharge the patient on a treatment plan that will keep their glucoses at goal till seen by their primary care team.
   If A1C is above 8 percent, one should recommend full basal bolus therapy upon discharge for most patients. If A1C is above 6.5 percent but less than 8 percent, many patients can be controlled on oral hypoglycemic agents such as metformin and/or DPP-4 inhibitors. If needed, the patient can continue to use correction dose insulin as needed or add basal insulin to metformin with or without incretin therapy. Sulfonylurea use is discouraged due to high risk of hypoglycemia, especially in the elderly and renal impaired patient.

2. All patients new to diabetes should be discharged home with a glucose monitor and have instructions when to see their primary care team and where to receive further self-management training and education about their diabetes.

References

1. Umpierrez, GE et al. J Clin Endocrinol Metab 2002; 87: 978-982
2. Krinsley JS et al. Mayo Clin Proc. 2003; 78:1471-1478
3. Robbins JM et al. Med Care 2006; 44:292-296
4. The NICE-SUGAR Study Investigators. N Engl J Med. 2009; 360:1283-1297
5. The NICE-GLUCOSE Study Investigators. N Engl J Med. 2012; 367:1108-1118
6. Umpierrez, GE et al. Diabetes Care 2011; 34:1-6
7. Umpierrez, GE et al. GLUCO-CABG Trial. Diabetes June 2014; ADA oral presentation
8. Smiley D et al. GLUCO-CABG Trial: Cost Analysis. Diabetes June 2014; ADA poster presentation
9. Davidson, PC et al. Diabetes Care 2005; 28:2418-2423
10.  Davidson, PC et al. J Diabetes Sci and Technol. 2008; 2:369-375