Insulin therapy for the management of hyperglycemia in hospitalized patients

Abstract

It has long been established that hyperglycemia with or without a prior diagnosis of diabetes increases both mortality and disease-specific morbidity in hospitalized patients and that goal-directed insulin therapy can improve outcomes. This article reviews the pathophysiology of hyperglycemia during illness, the mechanisms for increased complications and mortality due to hyperglycemia and hypoglycemia, and beneficial mechanistic effects of insulin therapy and provides updated recommendations for the inpatient management of diabetes in the critical care setting and in the general medicine and surgical settings.

Fig. 1

Pathogenesis of hyperglycemia. Hyperglycemia during acute illness results from increased hepatic glucose production and impaired glucose use in peripheral tissues. Excess counterregulatory hormones (glucagon, cortisol, catecholamines, and growth hormone) increase lipolysis and protein breakdown (proteolysis) and impaired glucose use by peripheral tissues. Hyperglycemia causes osmotic diuresis that leads to hypovolemia decreased glomerular filtration rate and worsening hyperglycemia. At the cellular level, increased BG levels results in mitochondrial injury by generating reaction oxygen species and endothelial dysfunction by inhibiting nitric oxide production. Hyperglycemia increases levels of inflammatory cytokines, such as TNF-α; IL-6, leading to immune system dysfunction; and plasminogen activator inhibitor-1 and fibrinogen, causing platelet aggregation and hyper-coagulable state. These changes can eventually lead to increased risk of infection, impaired wound healing, multiple organ failure, prolonged hospital stay, and death.

Fig. 2

Example of insulin infusion protocol. Essential elements that increase protocol success of CII are (1) rate adjustment considers the current and previous glucose value and the current rate of insulin infusion, (2) rate adjustment considers the rate of change (or lack of change) from the previous reading, and (3) frequent glucose monitoring.

Fig. 3

Use of insulin ordering forms to prescribe basal/bolus insulin programs. Insulin order forms are useful to illustrate and encourage the use of the 3 components of a patient-tailored insulin program (eg, basal, nutritional, and supplemental/correction).