Patients with type 1 or type 2 diabetes mellitus are frequently admitted to a hospital, usually for treatment of conditions other than the diabetes [1,2]. In one study, 25 percent of patients with type 1 diabetes and 30 percent with type 2 diabetes had a hospital admission during one year; patients with higher values for hemoglobin A1C (A1C) were at highest risk for admission . The prevalence of diabetes rises with increasing age, as does the prevalence of other diseases; both factors increase the likelihood that an older person admitted to a hospital will have diabetes.
Much of what was formerly done in hospital, including many surgical procedures, complex diagnostic testing, or treatment of community-acquired infections, is now done in a clinic or at home. However, the presence of diabetes might precipitate admission of a patient who would otherwise be treated as an outpatient . Whether in hospital or not, glycemic control is likely to become unstable in these patients because of the stress of the illness or procedure, the concomitant changes in dietary intake and physical activity, and the frequent interruption of the patient's usual antihyperglycemic regimen.
Once in the hospital, the length of stay and cost are greater for patients with diabetes than for those without it [1,4]. Efficient treatment of diabetes in hospital may be an important factor in limiting the costs of care. However, as mentioned below, firm data on optimal in-hospital treatment are sparse.
The treatment of patients with diabetes who are admitted to the general medical wards of the hospital for a procedure or intercurrent illness is reviewed here. The treatment of hyperglycemia in critically ill patients, the perioperative management of diabetes, and the treatment of complications of the diabetes itself, such as diabetic ketoacidosis, are discussed separately. (See "Glycemic control and intensive insulin therapy in critical illness" and "Perioperative management of blood glucose in adults with diabetes mellitus" and "Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Treatment" and "Management of hypoglycemia during treatment of diabetes mellitus".)
GOALS IN THE HOSPITAL SETTING
The main goals in patients with diabetes needing hospitalization are to minimize disruption of the metabolic state, prevent an untoward result, and return the patient to a stable glycemic balance as quickly as possible. These goals are not always easy to achieve. On the one hand, the stress of the acute illness tends to raise blood glucose concentrations. On the other hand, the anorexia that often accompanies illness or the need for fasting before a procedure tends to do the opposite. Because the net effect of these countervailing forces is not easily predictable in a given patient, the target blood glucose concentration is usually higher than when the patient is stable.