Proper Administration of Insulin Can Reduce Complexity of Patient's Hospital Course

In-hospital management of the patients with diabetes poses many challenges but also a unique opportunity to improve glycemic control and patient care.

Lillian Lien, MD, director, Division of Endocrinology and Professor of Medicine, University of Mississippi Medical Center, Jackson, addressed four questions pertaining to inpatient diabetes management.

What is the optimal blood glucose range for medical inpatients and intensive care unit (ICU) patients?

In the ICU setting, intensive insulin therapy to maintain blood glucose values between 80 and 110 mg/dL reduced ICU mortality and in-hospital mortality compared with conventional treatment with maintenance values between 180 and 200 mg/dL,1 but later the NICE-SUGAR study showed that intensive glucose control increased mortality among adults in the ICU .2

“In the end, what is critical is the concept of moderation” which appears to be maintenance blood glucose values between 144 and 180 mg/dL, said Dr. Lien. The American Diabetes Association (ADA) subsequently established 140 to 180 mg/dL as a target glucose range for most critically ill patients.3

Should I always stop oral medications in my patients with diabetes, and what oral hypoglycemic agents are safe and effective to use in the inpatient setting?

Insulin is the preferred medication for glycemic control in most hospitalized patients with type 2 diabetes, according to the ADA.4

The concern over continuing outpatient oral or noninsulin injectable agents is the potential hemodynamic and/or nutritional changes that often occur in the hospital. “Insulin is more flexible and the safest option,” she said. Stability in nutritional status and hemodynamics and a return to baseline renal and liver function are circumstances in which reinstitution of home regimens, including oral agents, is safe to consider.

Randomized controlled trials have shown efficacy for both DPP IV inhibitors and GLP1-receptor agonists as oral agents in the inpatient setting.4 However, consider discontinuing saxagliptin and alogliptin in patients who develop heart failure. “I would argue against the use of those agents at all in the inpatient setting,” she said.

SGLT2 inhibitors are not recommended for routine in-hospital use, especially in cases of severe illness, during fasting, and before surgical procedures.

The ADA states that basal insulin or a basal plus bolus correction insulin regimen is the preferred treatment for noncritically ill hospitalized patients with poor oral intake or those who are taking nothing by mouth, and an insulin regimen with basal, prandial, and correction components is preferred for noncritically ill hospitalized patients with good nutritional intake.4 The traditional sliding-scale insulin regimens are ineffective as monotherapy and are generally not recommended.5

The key to dosing subcutaneous insulin is to use a weight-based total daily dose. For patients with type 1 diabetes, start with 0.1 to 0.5 U/kg/day, and for those with type 2 diabetes, 0.3 to 0.7 U/kg/day, but some patients may require >1 U/kg/day.6 One-half of the daily dose is administered once daily as a long-acting peakless insulin, and one-sixth is administered before breakfast, lunch, and dinner as rapid-acting insulin.1 Never hold basal insulin in type 1 diabetes, unless blood glucose is <80 mg/dL.

What is the distinction between management of diabetic ketoacidosis (DKA) and hyperosmolar (nonketotic) hyperglycemic syndrome (HHS)?

Fluids are important in the management of DKA, but the mainstay of treatment is insulin, ideally IV infusion of regular insulin but alternatively frequent subcutaneous injections of rapid-acting insulin analogs.7 When serum glucose reaches 200 mg/dL, reduce the drip rate, but maintain serum glucose at 150 to 200 mg/dL until resolution of DKA. Bicarbonate infusion is rarely required; guidelines recommend administration only in patients with DKA with a venous pH <6.9.8

While patients with HHS are also insulin deficient, they have higher insulin concentrations with lower cortisol, growth hormone, and glucagon than patients with DKA. It requires a plasma glucose >600 mg/dL and a serum osmolality >320 mg/dL. When serum glucose reaches 300 mg/dL, reduce the drip rate but maintain serum glucose at 200 to 300 mg/dL until the patient is mentally alert.7

How should elevated blood sugars and diabetes be managed in the perioperative setting?

More than 1 decade of data have shown that glycemic control decreases the risk for infection and improves morbidity and mortality in the surgical patient.9,10 The target range for blood glucose in the perioperative period is 80 to 180 mg/dL,5 “with no reason to do tighter control,” she said. SGLT2 inhibitors should be discontinued 3 to 4 days before surgery, and metformin should be held on the day of surgery. Any other glucose-lowering agent should be held the morning of surgery.5

When the patient is NPO, meal-time bolus insulins should be held. With longer-acting insulin, the ADA recommends to give half of the NPH dose the morning of surgery.5 Reducing the insulin dose by 25% the evening before surgery can help to achieve perioperative target glucose levels with a low risk for hypoglycemia.5 Monitor blood glucose every 2 to 4 hours while NPO.

Disclosure

Consultant: Novo Nordisk, Sanofi-Aventis, Merck, Eli Lilly, Tandem

Book royalties: Springer, Inc.

References

  1. Lien LF, Bethel MA, Feinglos MN, et al. In-hospital management of type 2 diabetes mellitus. Med Clin North Am 2004;88:1085-1105.
  2. NICE-SUGAR study investigators; Finfer S, Chittock DR, Su SY-S, et al. Intensive versus conventional glucose control in critically ill patients. N Engl J Med 2009;360:1283-97.
  3. American Diabetes Association. 15. Diabetes care in the hospital: standards of medical care in diabetes—2019. Diabetes Care 2019;37(Suppl 1):S173-S181.
  4. American Diabetes Association. 15. Diabetes care in the hospital: standards of medical care in diabetes—2020. Diabetes Care 2020;43(Suppl 1):S193-S202
  5. American Diabetes Association. 15. Diabetes care in the hospital: standards of medical care in diabetes—2021. Diabetes Care 2021;44(Suppl 1):S211-S220.
  6. Lien LF, Cox ME, Feinglos MN, Corsino L (eds). Glycemic control in the hospitalized patient. 1st edition. Springer-Verlag, New York City, 2010.
  7. Kitabchi AE, Umpierrez GE, Miles JN, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care 2009;32:1335-1343.
  8. Umpierrez G, Korytkowski M. Diabetes emergencies—ketoacidosis, hyperglycaemic hyperosmolar state and hypoglycaemia. Nat Rev Endocrinol 2016;12:222-232.
  9. Furnary AP, Gao G, Grunkemeier GL, et al. Continuous insulin infusion reduces mortality in patients with diabetes undergoing coronary artery bypass grafting. J Thorac Cardiovasc Surg 2003;125:1007-1021.
  10. Matros E, Aranki SF, Bayer LR, McGurk S, Neuwalder J, Orgill DP. Reduction in incidence of deep sternal wound infections: random or real? J Thorac Cardiovasc Surg 2010;139:680-685.

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