Why control diabetes and hyperglycemia in the hospital?
What are the goals of glycemic management in critical care and noncritical care settings?
When should patients be treated with oral agents, with subcutaneous insulin, and with continuous insulin infusions?
Is it safe to prescribe subcutaneous insulin for the first time in a hospitalized patient?
How should insulin orders be adjusted in response to poor inpatient glucose control?
What should be considered when discharging a patient with diabetes or inpatient hyperglycemia?
How may the quality of glucose management be improved in hospital settings?
Diabetes mellitus is common in hospitalized patients. In 2007, diabetes was listed as a diagnosis in approximately 19% of all hospital discharges in the United States. Because discharge diagnoses may not capture undiagnosed diabetes or hospital-related hyperglycemia, the true prevalence of diabetes or hyperglycemia in hospitalized patients is likely much higher. For example, in one study of 1886 general medicine and surgery admissions, hyperglycemia (defined as a fasting plasma glucose of ≥ 126 mg/dL or a random plasma glucose of ≥ 200 mg/dL) was found in 38% of patients. Of these, 68% had known diabetes, but the other 32% had no previous diagnosis and consisted of patients with undiagnosed diabetes, “prediabetes” unmasked by the stress of illness, and pure “stress hyperglycemia.”
Hyperglycemia is associated with worse outcomes among hospitalized patients, including infections, increased length of stay, decreased independent living after discharge, and increased mortality. Hyperglycemia among known diabetics in the hospital carries a 2.7 relative risk of in-hospital death; even more dramatic is the 18-fold increased risk of death associated with hyperglycemia among those without a previous diagnosis of diabetes. Similar results have been seen in patients with pneumonia, myocardial infarction, chronic obstructive pulmonary disease, stroke, and those receiving total parenteral nutrition. Some of this excess mortality reflects the role of hyperglycemia as a marker for physiologic stress and severity of underlying disease. However, even when rigorous adjustment for severity of illness is conducted, excess mortality remains.
Does correcting inpatient hyperglycemia improve outcomes? In the noncritical care setting, this question has remained unanswered until recently.
RABBIT Surgery was a dual-site randomized controlled trial of 211 patients with type 2 DM admitted to general surgery services. The intervention group received a basal-bolus regimen with glargine once daily and glulisine before meals with a goal pre-meal glucose of 100–140 mg/dL. The control group received sliding scale regular insulin 4 times daily for glucose > 140 mg/dL. Mean glucose for the hospitalization was 157 vs. 176 mg/dL in favor of the intervention. Proportion of patients with any glucose < 40 mg/dL was 3.8% in the intervention group and 0% in the control group. Most importantly, the primary outcome, a composite of hospital complications including postoperative wound infection, pneumonia, respiratory failure, acute renal failure, and bacteremia, occurred in 24% in the control group and only 9% in the intervention group (p = .003; number needed to treat of 7 to prevent one complication). In the critical care setting, several studies of tight glycemic control have been performed, with mixed results. Early studies, such as the Leuven study conducted by van den Berghe, et al, in surgical intensive care unit (ICU) patients, were clearly positive. In Leuven I, patients were randomized to an insulin infusion protocol triggered when the blood glucose was > 100 mg/dL or a protocol that was triggered when glucose was > 215 mg/dL. The mean achieved glucose was 103 mg/dL vs. 153 mg/dL. Outcomes in the intervention arm included a 46% reduction in sepsis, 41% reduction in the need for dialysis, 50% reduction in blood transfusions, 44% reduction in polyneuropathy, and a 34% reduction in inpatient mortality. However, subsequent studies ...