Inpatient management of diabetes and hyperglycemia
1. Does evidence support intensive management of blood glucose in the hospital setting?
Although it is well established that hyperglycemia can lead to adverse patient outcomes, there is controversy over what degree of glycemic control is most appropriate. The largest randomized controlled trial (RCT), the Normoglycemia in Intensive Care Evaluation—Survival Using Glucose Algorithm Regulation (NICE-SUGAR) study, demonstrated a higher risk of mortality in patients with tight glycemic control (blood glucose [BG] target 81-108 mg/dL) than in those with standard glycemic control (BG target 144-180 mg/dL). The increase in mortality is thought to be partially due to the increase in hypoglycemia (≤ 40 mg/dL) seen in the intensively treated group. Although this study corroborated previous suggestions that glycemic control is important, it did underscore the risks of hypoglycemia and relaxing of glycemic targets.
2. What are the glycemic targets for the critically ill patient population?
The American Diabetes Association (ADA) recommendations are to initiate insulin therapy for treatment of hyperglycemia at a threshold of no greater than 180 mg/dL. Insulin therapy should then be titrated to maintain glycemic levels between 140 and 180 mg/dL. The glycemic goal can be further lowered to 110 to 140 mg/dL in select patients as long as it can be attained without hypoglycemia. It is further recommended that all patients entering the hospital undergo glucose testing to detect previously undiagnosed hyperglycemia that will require treatment.
3. What are the glycemic targets for non–critically ill patients?
There is only one RCT that examines the effect of glycemic control in non–intensive care unit (ICU) settings. The Randomized Study of Basal-Bolus Insulin Therapy in the Inpatient Management of Patients with Type 2 Diabetes Undergoing General Surgery (RABBIT 2 Surgery trial) showed that a basal-bolus insulin regimen was associated with fewer hospital complications than sliding-scale insulin therapy in the general surgery population. In addition, a number of observational trials have shown an association between hyperglycemia and adverse events such as prolonged hospital stays, infection, and mortality. The ADA’s current recommendations are to maintain premeal blood glucose targets at less than 140 mg/dL and random BG values at less than 180 mg/dL. In patients with a history of tighter outpatient glycemic control, the target can be lowered with the avoidance of hypoglycemia.
4. What are the inpatient glycemic targets for pregnant patients?
Blood glucose goals for pregnancy are tighter than those for the general population. Hyperglycemia during pregnancy is associated with many adverse outcomes, including macrosomia, congenital abnormalities, fetal hyperinsulinemia, and fetal mortality. For patients with gestational diabetes, the recommendations are a fasting blood glucose level lower than 95 mg/dL, a 1-hour postmeal blood glucose of 140 mg/dL or less, and a 2-hour postmeal blood glucose level of 120 mg/dL or less. For patients with preexisting diabetes, the ADA recommends that premeal, bedtime, and nocturnal glucose levels remain between 60 and 99 mg/dL and that peak postmeal glucose levels remain between 100 and 129 mg/dL.
KEY POINTS 1: TARGET GLUCOSE LEVELS FOR HOSPITALIZED PATIENTS5. Which patients are at high risk for hyperglycemia during their hospital stay?
Numerous factors can lead to hyperglycemia in patients with and without a preexisting diagnosis of diabetes. These situations include initiation of glucocorticoid therapy, enteral or parenteral nutrition, immunosuppressive agents, and periods of increased metabolic stress. It is recommended that all patients undergo glucose monitoring if they are receiving therapy that may cause hyperglycemia. If hyperglycemia occurs, appropriate treatment should be given using glycemic goals consistent with those for someone with known diabetes. The ADA recommends that a hemoglobin A1C (HbA1C) level be measured in all patients with diabetes admitted to the hospital if the results of testing in the previous 2 to 3 months are not available.
6. What is the best treatment for inpatient management of diabetes?
Insulin therapy, given as an intravenous (IV) infusion or subcutaneous injections, is the safest and most effective way to treat hyperglycemia in the hospital setting. Insulin is effective and can be rapidly adjusted to adapt to changes in glucose levels or food intake. It is also recommended that standardized insulin protocols be used whenever available.
7. What is an intravenous insulin infusion and why is it used in critically ill patients?
An intravenous insulin infusion is composed of 1 unit of regular human insulin per 1 mL of 0.9% NaCl (normal saline). When given intravenously, regular insulin has a rapid onset and short half-life, allowing for quick adjustment of insulin doses to achieve appropriate glycemic control.
8. At what rate should an insulin infusion be started?
An insulin infusion is usually initiated at 0.1 unit per kg body weight. Alternately, the starting dose can be based on the current blood glucose level, with rates varying from 1 to 7 units per hour depending on the severity of hyperglycemia. An initial bolus of regular insulin is also generally given if blood glucose levels are higher than 150 mg/dL at the start of the insulin infusion.
9. How should the IV insulin infusion rate be adjusted?
