Before accepting these recommended glycemic targets, review the shortcomings of the literature supporting them and consider institutional and individual patient factors that might modify the glycemic target.
Insulin has beneficial vascular and anti-inflammatory effects in its own right, making it difficult in some studies to distinguish the benefit of glucose lowering from the benefit of the insulin used to attain improved control.
The majority of studies supporting inpatient glycemic targets are observational or non-randomized. Some use admission blood glucose concentrations as the sole measure of glucose control.
While most of these studies used valid methods to control for severity of illness and co-morbidities, these methods are not perfect. In some cases, hyperglycemia may have been a marker of a more stressed and sick patient rather than an independent source of adverse outcome.
The dramatic results from the first van den Berghe study have proved difficult to replicate, in part because other investigators have had difficulty achieving stringent glycemic targets safely. Two international multicenter studies recently stopped enrollment due to excess rates of hypoglycemia, but the studies have not yet been published in final form.28-29
Finally, it bears repeating that the proposed glucose targets for noncritically ill patients are based on essentially no clinical trial data in that population. In part, the glycemic targets reflect the evidence derived from landmark outpatient randomized trials.30-31 In the outpatient setting, insulin requirements and nutritional intake are far more reliable than the inpatient setting, where the iatrogenic induction of excessive hypoglycemia is a valid concern.
Safe Glycemic Control
Rapidly fluctuating nutritional status, changing insulin requirements, varied levels of expertise, and hand-offs between geographic locations and providers are all common in the inpatient setting.
Aggressively pursuing glycemic targets without having systems and safeguards in place could lead to net harm.
The AACE recently identified these barriers and recommended a multidisciplinary team approach, reliable metrics, and a standardized method for insulin protocols, orders, and hypoglycemia prevention and treatment techniques.32
Both the AACE and SHM have produced toolkits to assist institutions to safely achieve improved glycemic control and care.33-34 The SHM Glycemic Control Task Force recently summarized key concepts to emphasize in formulating protocols and order sets in the noncritical care setting (see Table 2, left).
Stringent glycemic targets recommended by the ADA and the AACE may be appropriately moderated in centers that do not yet have the systems in place to achieve those goals safely.
Your glycemic target need not be identical to the ADA and AACE glycemic targets but should be similar to them. Examples of glycemic targets for noncritically ill inpatients are shown in Table 3 (see p. 48).
The glycemic target should be actionable, in that some institutionally endorsed action should result when a patient’s glycemic target is consistently not met.
Back to the Case
Your patient has an active infection, a glucose of 198 mg/dL and an elevated HbA1c. You hold the oral agents and start a basal bolus insulin regimen.
You generate an estimate for a safe insulin total daily dose of 60 units (100 kg x 0.6 units per kg for an obese, type 2 diabetes patient), and administer half as basal insulin, with the remaining 30 units distributed as rapid acting insulin in three divided doses. Your orders include routine glucose monitoring, and you plan to adjust the insulin daily as needed to adhere to the institutional glycemic target for noncritically ill patients of 90 to 150 mg/dL. TH