Inpatient hyperglycemia management: A practical review for primary medical and surgical teams

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ABSTRACTInpatient hyperglycemia is common and is associated with an increased risk of hospital complications, higher healthcare resource utilization, and higher in-hospital mortality rates. Appropriate glycemic control strategies can reduce these risks, although hypoglycemia is a concern. In critically ill patients, intravenous (IV) insulin is most appropriate, with a starting threshold no higher than 180 mg/dL. Once IV insulin is started, the glucose level should be maintained between 140 and 180 mg/dL. In noncritically ill patients, basal-bolus regimens with basal, prandial, and correction components are preferred for those with good nutritional intake. In contrast, a single dose of long-acting insulin plus correction insulin is preferred for patients with poor or no oral intake. Measuring hemoglobin A1c at admission is important to assess glycemic control and to tailor the treatment regimen at discharge.


  • Hyperglycemia in hospitalized patients, with or without diabetes, is associated with adverse outcomes.
  • Measurement of hemoglobin A1c is recommended in all patients at hospital admission.
  • Insulin administration is the preferred way to control hyperglycemia in hospitalized patients, with a starting threshold below 180 mg/dL then maintaining a level between 140 and 180 mg/dL.



Hyperglycemia in hospitalized patients, with or without diabetes, is associated with adverse outcomes including increased rates of infection and mortality and longer hospital length of stay.1–3 The rates of complications and mortality are even higher in hyperglycemic patients without a history of diabetes than in those with diabetes.1,2 Randomized clinical trials in critically ill and noncritically ill hyperglycemic patients demonstrate that improved glycemic control can reduce hospital complications, systemic infections, and hospitalization cost.4–6 However, intensive glycemic therapy is associated with increased risk of hypoglycemia, which is independently associated with increased morbidity and mortality in hospitalized patients. The concern about hypoglycemia has led to revised blood glucose target recommendations from professional organizations and a search for alternative treatment options.

This manuscript provides a review of updated recommendations for the management of inpatients with hyperglycemia in the critical care and general medical and surgical settings.


A substantial body of evidence links hyperglycemia in critically ill patients to higher rates of hospital complications, longer hospital stay, higher healthcare resource utilization, and greater hospital mortality.7,8 Although evidence from several cohort studies and randomized clinical trials suggests that tight glucose control can reduce hospital complications and mortality,9,10 this target has been difficult to achieve without increasing the risk of severe hypoglycemia. In addition, data from trials using intense glycemic control in patients in the intensive care unit (ICU) have failed to show a significant improvement in mortality and, in some instances, showed increased mortality risk associated with the therapy.11,12

The recommended target glucose levels are 140 to 180 mg/dL for most ICU patients.13 In agreement with this, the recent GLUCO-CABG trial reported no significant differences in the composite end points of complications and death between an intensive glucose target of 100 to 140 mg/dL and a conservative target of 141 to 180 mg/dL after cardiac surgery.14


In general medical and surgical patients, a strong association has been reported between hyperglycemia and prolonged hospital stay, infection, and disability after hospital discharge.1,15,16 For example, the risk of postoperative infections in patients undergoing general surgery was estimated to increase by 30% for every 40 mg/dL rise in glucose over normo­glycemia (< 110 mg/dL).16 In general, appropriate glycemic control to maintain recommended glycemic levels in noncritically ill patients can reduce the risks and improve outcomes.


Hypoglycemia, defined as glucose less than 70 mg/dL, is a common complication of hyperglycemia treatment.17 Severe hypoglycemia is defined as glucose less than 40 mg/dL.18 The incidence of hypoglycemia in ICU trials ranged between 5% and 28%, depending on the intensity of glycemic control,19 and between 1% and 33% in non-ICU trials using subcutaneous (SC) insulin therapy.20 The most important hypoglycemia risk factors include older age, kidney failure, change in nutritional intake, interruption of glucose monitoring, previous insulin therapy, and failure to adjust therapy when glucose is trending down or steroid therapy is being tapered.21,22

In hospitalized patients with diabetes, hypoglycemia has been associated with poor outcomes, including a 66% increased risk of death within 1 year and 2.8 days longer hospital stay compared with patients without hypoglycemia.23 Hypoglycemia also has been associated with prolonged QT interval, ischemic electro­cardiogram changes, angina, arrhythmias, and sudden death in patients with type 1 diabetes.24 Despite these observations, other studies have reported that the increased in-hospital mortality rate is limited to patients with spontaneous hypoglycemia rather than drug-associated hypoglycemia,25 raising the possibility that hypoglycemia may represent a marker of disease burden rather than be a direct cause of death.


Clinical guidelines recommend glucose measurement in all patients admitted to the hospital.13,26 Patients with hyperglycemia (glucose > 140 mg/dL) and patients with a history of diabetes should undergo bedside point-of-care glucose testing before meals and at bedtime. Premeal testing should be done close to the time of the meal tray delivery and no longer than 1 hour before meals. For patients taking nothing by mouth or receiving continuous enteral nutrition, point-of-care testing is recommended every 4 to 6 hours.

Hemoglobin A1c (HbA1c) should be measured in patients with hyperglycemia and in those with diabetes if it has not been performed in the preceding 2 to 3 months. In hyperglycemic patients without a history of diabetes, an HbA1c of 6.5% or greater suggests that diabetes preceded hospitalization. In patients with diabetes, the HbA1c can help assess glycemic control prior to admission and tailor the treatment regimen at discharge.13,26


Major guidelines for treatment of hyperglycemia in a hospital setting

Glycemic targets recommended by several organizations are shown in Table 1. For critically ill patients, most societies recommend glucose targets below 180 mg/dL, with the lower limit being anywhere from 110 to less than 150 mg/dL.

For patients in non-ICU settings, the Endocrine Society26 and the American Diabetes Association/American Association of Endocrinologists13 practice guidelines recommend premeal glucose levels below 140 mg/dL, and below 180 mg/dL if checked randomly. Higher glucose ranges (< 200 mg/dL) may be acceptable in terminally ill patients or in patients with severe comorbidities.26 Guidelines from the Joint British Diabetes Societies recommend targeting glucose levels between 108 and 180 mg/dL with an acceptable range of between 72 and 216 mg/dL.27

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