T ight glycemic control in the hospitalized patient is not a simple task. Hospitalized patients are characterized by high levels of counterregulatory hormones (catecholamines, cortisol, and growth hormone) and cytokines that vary greatly in the context of sepsis, burns, hypoxia, cardiovascular disease, pain, surgery, and trauma. In addition, inpatients have unpredictable eating times and little to no physical activity. Each of the major classes of oral glycemic agents has significant limitations for inpatient use and provides little flexibility or opportunity for titration in a setting where acute changes demand these qualities. As a result, slidingscale insulin (SSI) regimens are often used to treat hyperglycemia in patients with or without diabetes in these clinical situations.
SSI usually consists of rapid-acting or regular insulin ordered in a specified number of units for a given degree of hyperglycemia without regard to the timing of food, any preexisting insulin administration, or even individualization of a patient's sensitivity to insulin. This is not a physiologic approach to insulin management and not an ideal strategy for managing hyperglycemia. Because many SSI regimens do not initiate therapy until the blood glucose level is more than 200 mg/dL, SSI uses hyperglycemia as a threshold. This allows hyperglycemia to persist for long periods without intervention. In turn, SSI is reactive instead of proactive. With SSI, the current dose of insulin is based on the inadequacy of the previous dose, creating a "chase-your-tail" phenomenon. In addition, once the SSI regimen begins, glycemic control is rarely assessed by a physician until blood glucose is dangerously low or high (Ο½60 or ΟΎ400 mg/dL). Finally, SSI provides no basal insulin. Hospitalized patients with stress-induced hyperglycemia require not only postprandial insulin but also basal insulin to control blood glucose between meals and at night.
Evidence supporting SSI as a primary method of blood glucose control in diabetic patients is lacking. A search of MEDLINE for the period from 1966 to 2003 with the terms "sliding scale insulin," "sliding scale," and "sliding" combined with "insulin" yielded a total of 52 publications, none of which showed a benefit of sliding-scale insulin in improving glycemic control or clinical outcomes. Retrospective and nonrandomized studies confirmed that SSI is associated with more hyper-and hypoglycemia with longer hospital stays. [1][2][3] Queale et al. published the largest prospective cohort study (n Ο 171) of diabetic patients on SSI. 4 More than 40% had at least one episode of hyperglycemia (ΟΎ300 mg/dL), and 25% had more than one episode. Use of SSI alone increased the likelihood of hyperglycemia 3-fold. Hypoglycemia occurred in 23%. Despite this poor performance in controlling blood glucose, the SSI remained unadjusted throughout the hospital stay for more than 80% of patients. In total, the clinical studies and clinical reviews on SSI confirmed that it is an inappropriate approach to blood